Service Unavailable Errors in IIS 7 Are Killing Me

0 comments suggest edit

UPDATE: Problem solved thanks to some members of the IIS 7 team!

I am at my wits end trying to get IIS 7 to work on my Vista Ultimate box and I have tried everything I can think of.

I’ve tried every step in the following tutorial, Where did my IIS7 Server go? Troubleshooting “server not found” errors. I also tried every step in this post on troubleshooting “service unavailable” errors. Trust me when I say I went through every one of these steps twice. Rob Conery can back me up on this because he watched me do so in a when I shared my desktop with him via GoToMeeting.

As far as I can tell, IIS 7 or http.sys must be corrupted somehow and the only thing left for me to try is to repave my machine and reinstall Vista. Unless of course one of my dear readers has an insight that will help me solve this, or knows someone who does.

The Problem

I’m running Vista Ultimate which has IIS 7 installed. When I navigate to http://localhost/ or http://localhost/iisstart.htm, I get an HTTP Error 503 Service Unavailable message.

What I’ve Tried

Confirmed that Skype is not listening to port 80 (Skype tries to listen on port 80 by default).

​1. Confirmed that App Pools were configured correctly and started.

​2. Ran the following command: appcmd list apppools which produced the output:

APPPOOL "DefaultAppPool" (MgdVersion:v2.0,MgdMode:Integrated,state:Started) APPPOOL "Classic .NET AppPool" (MgdVersion:v2.0,MgdMode:Classic,state:Started)

​3. Confirmed that Website was started.

​4. Ran the following command: netstat -a -o -b which produced the output:

TCP [::]:80 METAVERSE:0 LISTENING 4Can not obtain ownership information

The 4 there is the PID which I confirmed to be System as in the NT Kernal & System.

​5. Confirmed bindings were configured in IIS Manager and set for localhost port 80.

​6. No error messages in the event log under System nor Application.

​7. Made sure that my user account and the Network Service account both have access to the c:\inetpub\wwwroot directory.

​8. Tried browsing to http://MYCOMPUTERNAME/, http://localhost:80/,, etc… (I was getting desparate).

​9. Tried changing the default AppPool’s managed pipeline mode to Classic.

​10. Tried changing the default AppPool’s .NET framework version to No Managed Code (recall that I am trying to request a static HTML page).

​11. Able to ping localhost.

​12. Tried to telnet localhost 80 and then issue the command GET / and received the same message.

​13. Double checked that all the Handler Mappings were enabled.

​14. Made sure Anonymous Authentication was enabled. Heck, I tried it with them all enabled and tried it with only Windows Authentication enabled.

​15. Authorization Rules has one rule: Mode=allow, Users=All Users.

​16. Enabled Failed Request Tracking. Nothing showed up in the logs.

​17. Uninstalled and reinstalled IIS 7.

​18. Tried pulling my hair out and rending my garments and sacrificing chickens^1^.

Any ideas?

So there you go. I’ve tried everything I can think of and now I appeal to you for help.

The funny thing is that this works on my Vista box at work and I compared every setting in IIS. This confirms in my mind that something got fubar’d. But I hesitate to repave my machine just yet in the hope that someone out there has some definitive answers for me.

^1^ No actual chickens were harmed in troubleshooting this problem.

Found a typo or error? Suggest an edit! If accepted, your contribution is listed automatically here.



72 responses

  1. Avatar for Damien Guard
    Damien Guard May 18th, 2007

    Try using "telnet localhost 80" followed by "GET /" hitting return and seeing what comes back.

  2. Avatar for Florian Krüsch
    Florian Krüsch May 18th, 2007

    Try instead of ?

  3. Avatar for Bill Staples
    Bill Staples May 18th, 2007

    Hi - try this: go to \windows\system32\inetsrv\ and run the following command:
    appcmd start DefaultAppPool
    If that doesn't work, shoot me an email and I'll help you debug it further.

  4. Avatar for Geri Langlois
    Geri Langlois May 18th, 2007

    I had a similar situation but no where near identical -- I only post this because it might give you some ideas of where to look.
    I was setting up an asp 1.1 site with an asp 2.0 app below it. I created a 1.1 app pool for the main site and applied it. After that I started getting the service unavailable error.
    In the end, after much hair pulling, I installed 1.1 SP1 on my machine and applied the app pool that it automatically created. It appears that the 1.1 framework installed with vista (ultimate) was out of sync with or unable to support IIS 7. The point is this is that it was a bad (incorrect) app pool that was the source of this issue and I wonder if that is what you should look at next. Hope this was helpful.

  5. Avatar for Scott
    Scott May 18th, 2007

    Have you tried Spy++ or the equivalent Sysinternals process spy program to see what's really going on in process 4?
    You could also try writing a small program that will attempt to listen to port 80 and rule out any freaky firewall problems or port conflicts. Or download Apache or some small web server and see if it can bind to port 80.
    Also you didn't mention looking at the event logs or IIS logs. I assume that you did, but what did they say? Did the IIS logs record the GET attempts? Does the system event log show anything funny? Isn't there some kind of "verbose" logging mode for IIS? Here's a module for IIS 7 logging

  6. Avatar for Scott
    Scott May 18th, 2007

    Oh more dumb troubleshooting tips.
    Can you serve up static HTTP pages on your box?
    Checked the permissions on wwwroot?

  7. Avatar for Haacked
    Haacked May 18th, 2007

    THanks Scott. I did check NTFS permissions. I am also attempting to load a static html page with no luck.
    I also created a brand new website with a static html page and couldn't load that.

  8. Avatar for Ayende Rahien
    Ayende Rahien May 18th, 2007

    The chicken thing is the problem.
    You really need to sacrifice at least one to honor IIS.

  9. Avatar for Eber Irigoyen
    Eber Irigoyen May 18th, 2007

    1 - tcpview
    2 - fiddler

  10. Avatar for Tony Bunce
    Tony Bunce May 18th, 2007

    This sounds like an App Pool issue to me. I have see it before when the user didn't have a profile. Running the bat file on this page has fixed it for me in the past:
    It says its only for 1.0 but I know it has fixed 1.1 problems for me before and maybe even 2.0 issues.
    You could also try aspnet_regiis -ua to uninstall just to see if that is the problem.
    The "Service Unavailable" is a page generated by IIS so i don't think any network level tools are going to help much.
    Is UAC enabled? Maybe try turning it off. You could also try enabling security auditing to see if some security issue is causing the problem.
    I think IIS is supposed to log something to event viewer when a worker process crashes, so make sure your event log isn't full and if it is clear it out or make it bigger.

  11. Avatar for engtech
    engtech May 18th, 2007

    Have you tried Apache?

  12. Avatar for Haacked
    Haacked May 18th, 2007

    @Damien - Still get the error.

  13. Avatar for Haacked
    Haacked May 18th, 2007

    @engtech, just like your blog. Funny content, but not so helpful. ;)
    I kid! I kid!

  14. Avatar for Mike Volodarsky
    Mike Volodarsky May 19th, 2007

    I just made a post about debugging start-up crashes that may be helpful in getting to the bottom of your problem.
    Check it out here:
    I am a bit suprised that you didnt see an event in the Windows "Application" event log, that indicates that the worker process has suffered an AV (or 5 of these, with a corresponding event in the System event log indicating that the application pool has entered rapid fail protection). Can you double-check whether these events are there?
    Let me know if the technique above does not work for you for some reason, or what you find out - feel free to leave comments on the post.
    Good luck,

  15. Avatar for Rick Strahl
    Rick Strahl May 19th, 2007

    Phil... Makes sure your AppPool that you have assigned to the app is actually running. In IIS 7 the AppPools can be stopped explicitly and that may get you the 503 error - I had that pop up on me a while back when the AppPool was shut down due too many failures.

  16. Avatar for Eric Kemp
    Eric Kemp May 19th, 2007

    You might want to take a look in:
    In that folder, you'll find applicationHost.config and applicationHost.config.clean.install
    These effectively represent the replacement for the MetaBase in IIS 6 and earlier. It might be worth doing a diff on the two files, or simply replacing the existing applicationHost.config with a copy of applicationHost.config.clean.install.

  17. Avatar for Haacked
    Haacked May 19th, 2007

    @Rick - I saw your post on that and I did make sure. If you take a look at step #2, you can see that both appPools are started. I also confirmed within IIS Manager. I also stopped and restarted both.
    @Eric - I see the following two files:
    - administration.config
    - applicationHost.config
    I don't see any files with the *.clean.install extension.

  18. Avatar for Haacked
    Haacked May 19th, 2007

    @Mike - Rapid Fail Protection would cause the appPools to stop, right?
    The appPools aren't stopped. I just checked again and they are still started. Again, I ran the command in step #2 above.

  19. Avatar for Eric Kemp
    Eric Kemp May 19th, 2007

    Hmm... the .clean.install files must not be created in all scenarios... However, I have both of them in two different Vista scenarios. Is this a new install, or an upgrade from XP?
    In any event, the idea is to get back to default settings. The .config file may linger even after an uninstall of IIS. It would be worth trying the uninstall and reinstall again, making sure that you clean out any residual settings, such as applicationHost.config, before reinstalling.

  20. Avatar for Mike Volodarsky
    Mike Volodarsky May 19th, 2007

    Can you answer the following questions for me?
    1) After making the request, do you see any processes called "w3wp.exe" in your task manager (be sure to show all proceses in all sessions)
    2) What is in your Windows "Application" event log? Are you seeing any events indicating why your worker processes are going away? I have never seen a case where an event is not logged.
    3) Have you followed the steps in

  21. Avatar for Scott Elkin
    Scott Elkin May 19th, 2007


  22. Avatar for Haacked
    Haacked May 19th, 2007

    1. I don't see w3wp.exe in my task manager. That's interesting.
    2. There's nothing in my application log related to this.
    3. I haven't tried downloading the windows debug symbol. I did share my desktop via GoToMeeting with a member of the IIS7 team who was as stymied as I was. We'll open a trouble ticket.
    If I have time tomorrow, I can run through all the steps in your post. I just wasn't sure if it was applicable given that there were no event log messages and the appPools are all started and never die.
    When I run appcmd list apppools I always get the same result, showing them started.

  23. Avatar for Jayson Knight
    Jayson Knight May 19th, 2007

    I can't be of much help other than to say that if you can't even get an HTML page to render then something is seriously wrong w/ the core of IIS. Did you check all your mappings/verb handlers at the root of IIS (above the web apps)? What about the IP inclusion list (blocking all IP addresses somehow)? Also, a more verbose reason should be listed in the http.sys error logs.

  24. Avatar for engtech
    engtech May 20th, 2007

    Wish I could be more helpful but I really don't know anything about using Microsoft development tools. I've been on a strict died of linux / open source software for years.

  25. Avatar for Haacked
    Haacked May 20th, 2007

    @Mike - I tried to go through your steps, but w3wpe.exe never gets started. Hmm....

  26. Avatar for nitro2k01
    nitro2k01 May 20th, 2007

    When hearing about your problems I could just tell you to try open source alternatives. (Which is generally not a bad idea)
    But from a pure malfunctioning point of view, FOSS software can laugh you in the face as well.
    For example, lately I've been struggling to get a FAMP server (FreeBSD, Apache, MySQL, PHP) to work on a SunBlade machine, a real exotic flavor. (These computers are non-Intel ones that usually run Solaris)
    It's a real b****, and so far I haven't got it to work properly. (The server just stops responding whenever I use PHP, with MySQL enabled, even if MySQL isn't used, sometimes it happens under other circumstances too)
    Where was I going with that? Oh yeah: Even if you don't choose to convert to Apache, etc., my advice is to let go of Vista for now. My own experience, sadly, is that Windows OS's don't get really mature until at least a year after the release, when initial bugs and holes are fixed.

  27. Avatar for Haacked
    Haacked May 20th, 2007

    @nitro - I understand the sentiment. But in this case, I have pretty much exactly the same setup at work. Vista running IIS7. So the fact that it doesn't work at home doesn't seem to be a Vista issue (nor an IIS7 issue) per se.
    It seems like somehow, my installation at home got corrupted. I could just reinstall IIS fully (someone told me I was missing a step in my previous attempt) but I'm working with a couple people on the IIS 7 team to see if we can't figure out *why* this is happening. Just in case it really is a problem in IIS 7 that they haven't seen before. I'm happy to help out.
    As for switching to Apache, not really feasible right this second. I'm trying to get my machine setup at home so I can work from home or work. So I need to be able to run the same webservers we use at work.
    However, I believe our product will work on Apache in theory. So it's definitely something I will setup in the future.

  28. Avatar for Haacked
    Haacked May 20th, 2007

    @engtech - I was joking about the "helpful" part. I love your blog.

  29. Avatar for Brian Chiasson
    Brian Chiasson May 20th, 2007

    HOST table anyone - are you sure that localhost has not been remapped? Here are the settings for localhost in my hosts file (left out the comments). localhost
    ::1 localhost
    I would also check any firewalls to make sure they are not blocking anything.

  30. Avatar for Mike Volodarsky
    Mike Volodarsky May 20th, 2007

    The steps may still be applicable assuming the problem is with IIS.
    I would try the following:
    1) Look in %systemdrive%\WINDOWS\system32\LogFiles\HTTPERR httperrX.log file to see if http.sys is rejecting the requests for some reason
    See if requests are causing entries to be written here, and if so, post them.
    If not:
    2) Follow the steps in the startup-debugging post.
    The basic thing we need to confirm is whether the request is getting into the worker process (even if its crashing and going away) - depending on this, the subsequent diagnostics will be much different.

  31. Avatar for Haacked
    Haacked May 20th, 2007

    Mike, I see a bunch of errors like this:
    2007-05-20 00:43:20 ::1%0 62458 ::1%0 80 HTTP/1.1 GET / 503 - N/A -
    I tried the debugging steps but it never broke into the debugger. It seems like w3wp.exe never starts.

  32. Avatar for Haacked
    Haacked May 20th, 2007

    @Brian, I have the same thing in my hosts file. I tried turning off the firewall during this whole episode.

  33. Avatar for you've been HAACKED
    you've been HAACKED May 21st, 2007

    The IIS 7 Team Rocks!

  34. Avatar for Community Blogs
    Community Blogs May 21st, 2007

    I recently wrote about some 503 Service Unavailable Errors with IIS 7 that had me completely stumped

  35. Avatar for Tom
    Tom July 26th, 2007

    "Cannot Read Configuration FILE"
    That's what the application log shows for me. I haven't gotten a simple page to show on Vista with IIS7 yet either. Definately frustrating.
    Why can't it read the config file? Seems like a security setting someplace.
    Any Ideas?

  36. Avatar for AliM
    AliM December 2nd, 2007

    I was frustrated by the same problem and the following solution worked for me...
    Can you check if you have leftover directory for pe-release version of framework in %windir%\Microsoft.Net\Framework (anything like v2.0.* other than v2.0.50727) - if so, delete those directories and restart the app-pool.


  37. Avatar for Kamil Czajko
    Kamil Czajko January 17th, 2008

    Hi Guys um I'm sure you would have already taken a look at this but I didn't see it mentioned, do you get any error messages or log entries when restarting the world wide web publishing service and just check that its logging on with the right credentials?
    Also bare in mind that some software can actually bind port 80 as well (ie anything that might let you tunnel such as putty or ems, certain trend products, and vmware.)
    You may also be blocked in vista if the network you are connected to is not a trusted network (network and sharing center-> customise next to every network it shows, yes EVERY network even ones that are not connected to anything such as VMware virtual adapters.) I like to set it to work zone as this seems to be the most logical but vista will block ports if even one of the networks it displays is set to unknown or public. I had a virtual server running vista and I had to setup a kvm as it would knock me off rdp everytime a virtual machine would be rebooted or it detected any change on the adapter. >.<
    Network Discovery may also need to be on.
    All the best

  38. Avatar for Hondo
    Hondo May 22nd, 2008

    Run these two commands to see if you have any URL reservations:
    Netsh http show servicestate
    Netsh http show urlacl
    If so, you may have to run something *like*:
    netsh http delete urlacl url=http://+:80/

  39. Avatar for Mark McLaughlin
    Mark McLaughlin July 16th, 2008

    My Service Unavailable error was fixed when I restarted my Application pool. I believe a programming error (trying to add a control to itself!) shut down my application pool.

  40. Avatar for Kami
    Kami August 14th, 2008

    I am having this same problem... One thing I've noted is when I hit the URL of my deployed website the Application Pool in IIS7 automatically make a transition from Started to Stopped.

  41. Avatar for Mike
    Mike August 20th, 2008

    After a year of successfull web hosting with IIS7 and windows vista home premium all of a sudden im getting these 503 service unavailable errors. But i do have a third party e-mail exchange server running on port 8080 that works fine so i know its IIS making the errors. Any ideas before i go home and start digging?

  42. Avatar for Nirre
    Nirre September 11th, 2008

    I have the same problem when running MOSS 2007 on IIS 7. I got it running by commenting out the IPv6 record (added by MOSS Search) in the Host File. Now its up and running.

  43. Avatar for Umesh
    Umesh October 9th, 2008

    The issue I had completely mirrors this one
    1. No worker process starting
    2. No event log entries
    3. No html even
    The issue I had was port 80 was reserved for some other user and I had to delete the url reservation as
    delete urlacl url="http:+:80"

  44. Avatar for Paul
    Paul October 15th, 2008

    @Nirre Thank you, that fixed my problem. I was about to reinstall my server ...

  45. Avatar for Waffle247
    Waffle247 October 26th, 2008

    Have you checked the user account you are using for the application pool in question has the correct rights to the virtual directories & other resources associated with your website?
    I just had a similar issue which I fixed by changing the AppPool account from my user account (mydomain/myusername) to the "local system" account on the machine - I actually have no idea what, when or how the changes to my user account permissions got made; I didn't do it so the only other person to blame round my way would be Bill Gates. Thankfully it's just my local dev machine so I can get away with arbritrary account changes, for production environments I'd suggest creating a new account, assigning it permissions to the resources you need and making a new AppPool then use that for your website.... IIS is soooo not helpful for dev work - MS go away and stop telling lies about ease of use to my boss!

  46. Avatar for CMZK
    CMZK November 28th, 2008


  47. Avatar for PMR
    PMR January 5th, 2009

    Thanks Umesh, this:
    delete urlacl url="http:+:80"
    solved my problem

  48. Avatar for John
    John January 20th, 2009

    Thank you Umesh!! I have been Googling for this problem for two days. Running the port reservation delete command in "netsh" on port 80 solved my problem. Thanks again...

  49. Avatar for Dostoy
    Dostoy January 23rd, 2009

    Make sure whatever account the application pool is using for it's identity is a member of the IIS_WPG local group.

  50. Avatar for Rjam
    Rjam February 5th, 2009

    I ran into this problem as well but not until i tried running 2 websites off the same server. Anyways, I am going to guess you are using the DefaultAppPool, try changing it to the Classic .NET AppPool, this is what I ended up doing in the end and eveything (both sites) are running normally.
    When I run a single web site off the server the DefaultAppPool works fine, but for some reason if I add another website to IIS it will not. Bug? Corrupted pool? I don't know, all I know is the Classic .NET AppPool solved all my problems.
    Hope this helps you out.

  51. Avatar for Muhammad Adnan
    Muhammad Adnan February 18th, 2009

    O com on man.. its not that much big issue as much you tried to get rid of...
    let me tell you a very common joke about microsoft windows...
    there were 3 friends in a car, 1 was chemical engineer, 1 was mechanical eng., 1 was microsoft engineer, suddenly car stopped due to some problem, chemical engineer said check its battery acid, oil, petrol and such things, mechanical eng. said open it and check its parts... and microsoft engineer said, o com on just open windows and close it again and try it will definitely work... ;)
    hope you got what i mean.. i got the same problem and google issue as every1 and find out your blog and till end i expected you will have given some solution but you were also looking for :D anyhow then i follow restart design pattern :D and run command iisreset in cmd and bingoooooooooooooooo! its back ;)
    best of luck...

  52. Avatar for saba
    saba March 25th, 2009

    The same error has been killing me for a couple of days. But after going through a lot of blogs I came up with a solution and wanted to share it with you guys.
    It started off with the error that service unavailable. To resolve that, I replicated the classic application pool and changed the Application pool of my web application to the new application pool. That got rid of service unavailable error.
    Then came "HTTP Error 401.2 - Unauthorized
    You are not authorized to view this page due to invalid authentication headers."
    For this I Enabled the anonymous authentication in IIS Manager. For details you can visit
    Then another error which was "HTTP Error 403.14 - Forbidden
    The Web server is configured to not list the contents of this directory."
    To solve this, I enabled the directory browsing for my web application IIS Manager.
    Finally, the last error was "The current identity (NT AUTHORITY\NETWORK SERVICE) does not have write access to 'C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files'. "
    This was resolved by giving full rights to the user NETWORK SERVICE for the folder C:\Windows\Temp.
    So at last I'm able to test my application.
    Best Regards.

  53. Avatar for dazx
    dazx January 26th, 2010

    Hi There,
    Mike thanks. Im problem solved.
    How i did.
    Unckecked IIS in Turn on/off.
    Restart PC.
    Reinstall IIS.
    Run cmd as administrator.
    cd C:\Windows\System32\inetsrv>
    appcmd list apppools
    go back to IIS manager restart DefaultAppPool.
    Hope will help

  54. Avatar for nishant
    nishant February 2nd, 2010

    I am on a shared hosting service. These days I am getting 503 error quite frequently. I am not able to know the exact reason. how could I Know the exact reason why it is happening?
    I know about rapid fail protection which cause application pool to shut down for a particular number of error in a fixed time. but what type of error these can be for example these are not html errors obviously, not complilation error, then what type of errors/failures can cause application pool shutdown.
    I have installed blog on my site and generaly when i view blog oages I get 503 error so what type of error/failure we could think of which can cause application pool to shutdown....

  55. Avatar for Nikita G.
    Nikita G. December 12th, 2010

    This can happen after you changed your account password.
    In this case, do the following:
    1. Go to services, sort them by log on account and set new password for the ones that are run using your account (not built-in one)
    2. Go to app pool properties and re-set your account name and password.

  56. Avatar for Daniel
    Daniel June 15th, 2011

    SOLVED------> DO a System Restore....
    Free Palestine.

  57. Avatar for lance lyons
    lance lyons July 5th, 2011

    I have a similar problem but not exactly the same. We have a new server (windows 2008 r2) that we are using as a TFS server. We also cant get the TFS site to come up when the app pool runs with the TFSSERVICE identity (this is a active directory service account that is a local admin on the box).
    I set up a test site and test app pool with a simple .html file. When the app pool for this site is set to run as Network Service or ApplicationPoolIdentity the site works and the html file renders.
    If I use my active directory account (local admin) or and other a/d account like TFSSERVICE, I get the HTTP Error 503. The service is unavailable and the app pool is shut down. The following error is in the event log.
    The identity of application pool test is invalid. The user name or password that is specified for the identity may be incorrect, or the user may not have batch logon rights. If the identity is not corrected, the application pool will be disabled when the application pool receives its first request. If batch logon rights are causing the problem, the identity in the IIS configuration store must be changed after rights have been granted before Windows Process Activation Service (WAS) can retry the logon. If the identity remains invalid after the first request for the application pool is processed, the application pool will be disabled. The data field contains the error number.
    I am guess the error number in the data field is 80070569 ?
    Any ideas?

  58. Avatar for George Tang
    George Tang August 16th, 2011

    @Lance, Try this post:

  59. Avatar for juju
    juju August 25th, 2011

    Server Error in '/' Application.
    The current identity (IIS APPPOOL\DefaultAppPool) does not have write access to 'C:\inetpub'.
    Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
    Exception Details: System.Web.HttpException: The current identity (IIS APPPOOL\DefaultAppPool) does not have write access to 'C:\inetpub'.
    please help me solve this issue.

  60. Avatar for Avnish
    Avnish September 6th, 2011

    Make a different app pool and select it while installing the service.
    It resolved the issue in my case.

  61. Avatar for C Haddy
    C Haddy January 25th, 2012

    Have you checked the Identity that your AppPool is running under in IIS? If the APPpool was set to run under a specific (custom) account (username and password), and you changed your Windows password, you will need to go and update the Identity's password on this AppPool. Good luck!

  62. Avatar for simon noyola
    simon noyola July 17th, 2012

    Opening IIS and Application Pools ensure "DefaultAppPool", and any other Application Pools your websites use. Click advanced settings for each of these. Ensure the "Load User Profile" is set to 'False'

    Also ensure that the "Set Application Pool Defaults" has the Load User Profile set to False.

  63. Avatar for JP Hellemons
    JP Hellemons August 1st, 2012

    I have had the exact same thing. also had issues when I used IISexpress. Finally found out that I had some global.asax which starts filling (webform) routes with the use of a db connection and found out that the only error I had was the password in the connectionstring... that caused iis to give 503 errors

  64. Avatar for full suppend
    full suppend September 10th, 2012

    Thanks to Dazx. I followed his advice. I went to IIS Manager and noticed that my DefaultAppPool is stopped. So I clicked Start and voila! It solved it! I remember installing Zend Server and I guess that installation was the culprit.

  65. Avatar for hlaprade
    hlaprade October 8th, 2012

    Hi Guys, like a lot of you guys I being having this same issue, I saw my worker process was empty, off course since app pool was stopped inmediatly. The thing is that I am new with this shared configuration so probably I look in odd places, I saw an error at the System Level log that cought my attention
    Application pool "XXXXX" is being automatically disable...
    and also
    At the application level log
    The Module DLL C:\Windows\System32\inetsrv\webdav.dll failled to load. The Data is error.
    I noticed that it was not install so I installed. Not sure why, if I ran into the reasson why that fixed my problem I will let you guys know!

  66. Avatar for Pummba
    Pummba October 10th, 2012

    @Nikita G. is right. It happened to me suddenly today and as I read @Nikita G. comment I realized that yesterday I had to change my windows account password.
    I went to the application pools and updated the user with the new password (Advanced Settings).
    It started working again!

  67. Avatar for Jadm
    Jadm October 19th, 2012

    Setting the Identity as LocalService Identity (right click on DefaultAppPool ->Set Default...) just worked fine...

  68. Avatar for Erzsebet
    Erzsebet November 19th, 2012

    Replacing for the web application in IIS
    Enabled protocols: net.tcp;http;https
    Enabled protocols: http
    helped me, Service Unavailable 503 disappeared

  69. Avatar for Shri Wangnekar
    Shri Wangnekar March 12th, 2013

    change the app pool mode from classic to integrated , that did the trick for me for the same error

  70. Avatar for Mehran Halimi Asl
    Mehran Halimi Asl May 19th, 2013

    I had they same problem, it is solved by:

    delete urlacl url=http://+:8080/

    it seems that port 8080 had problem

  71. Avatar for Roy
    Roy September 29th, 2015

    Thanks for your greatful post.
    I also refer very helpful and useful article
    Visit this helpful article

  72. Avatar for Mehmet AVŞAR
    Mehmet AVŞAR November 19th, 2016

    Any URL rewrite rules on server?