HTTP Error 503. The service is unavailable when port 80 is already free

1
votes

Before you go and suggest it as a duplicate of other IIS HTTP Error 503 questions, I have already tried many solutions available on SO and also on Google but the problem is not resolved. Below are the most popular solutions that I have found:

IIS - HTTP Error 503. The service is unavailable

Solve HTTP Error 503. The service is unavailable in IIS

In my case:

IIS is not working while the port 80 is open and free to use.

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As far as I know the error is caused if the application pool is not enabled (started) for the website in IIS.

I have already closed all other applications like Skype, Google Disk etc who can possibly use port 80 and checks if the port is in use or not.

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Then I looked into the Application Pools of IIS and found DefaultAppPool status stopped.

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After starting the DefaultAppPool I recheck my web and gets the same error.

And now the situation is like, DefaultAppPool status shows started until I don't hit any URL. Whenever I request any URL for my local websites or localhost, the browsers returns me the Service Unavailable error message and the DefaultAppPool status change to stopped automatically.

I have already tried the iisreset command but after resetting IIS the problem is still there.

2
c#asp.net.netiisiis-7
Basicly error 503 means that somthing is wrong in your code or in your web server. I would sugest the you'll try to change your website application pool to the asp.net 4 app pool (the second one in the list). I had the exact problem after installing framework 4.5. After moveing the application to the asp.net v4 it solved. – Tomer Klein
@Tomer Klein I have already change the Application pool to Asp.net 4 app pool but still same error and also created a custom app pool as test but the browser returns the same error. – Suhaib Janjua
Bytheway it gives the same either I access my deployed websites or simple localhost to check if the IIS is running or not. – Suhaib Janjua
So what event log shows? – Alexei Levenkov
Have you try looking in the windiws event viewer under application/system log? – Tomer Klein

2 Answers

2
votes

Most probably identity under which you are running your app pool i.e. administrator has wrong password or disabled. Try changing this identity to something like network service or local service or any other valid identity.

6
votes

There is an uncommon cause for 503 error. To fix this, follow these easy steps:

Run this command 

netsh http show urlacl

It will list all reserved urls, find the url with relevant port.

 Reserved URL            : http://+:80/
    User: NT SERVICE\Machine
        Listen: Yes
        Delegate: No
        SDDL: D:(A;;GX;;;S-1-5-21-2127521184-1604012920-1887927527-67210)

Then delete the entry with this command (replace the url part with yours):

netsh http delete urlacl http://+:80/

https://blogs.msdn.microsoft.com/webtopics/2010/02/17/a-not-so-common-root-cause-for-503-service-unavailable/