HTTP Error 503. The service is unavailable. App pool stops on accessing website

Question

There are number of posts on this and I have tried many a things by now. But to no avail. Myself a Winforms Developer basically, started working on this Web stuff few days b

Answer 1

Most of Time, it was occured due to AppPool Setting.

Check the following to resolve this

1. Check Apppool service is running.
2. Check Identity of AppPool.
3. Enter the new password if it has changed for that identity.

The following Images show these setting in IIS

Answer 2

Will this answer Help you?
If you are receiving the following message in the EventViewer

The Module DLL aspnetcorev2.dll failed to load. The data is the error.

Then yes this will solve your problem

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To check your event Viewer

1. press Win+R and type: eventvwr, then press ENTER.
2. On the left side of Windows Event Viewer click on Windows Logs -> Application.
3. Now you need to find some ERRORS for source IIS-W3SVC-WP in the middle window.

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if you receiving the previous message error then solution is :

Install Microsoft Visual C++ 2015 Redistributable 86x AND 64X (both of them)

Source

Answer 3

I was facing the same problem, and debugged it using the event logs. First it said that : "The description for Event ID 5059 from source Microsoft-Windows-WAS cannot be found".

I then turned on WAS using turn windows features on/off. Then i saw this in eventvwr "Microsoft-Windows-DistributedCOM cannot be found".

Finally I gave up and deleted the App Pool (that used to stop on accessing the website) and created it again, as it is. This resolved the problem.

Answer 4

I had a similar issue. I solved it by adding my user to the "Log on as a batch job" policy under "Local Security Policy" > "Local Policies" > "User Rights Assignment".

Answer 5

If you can run the website in Visual Studio debugger, then might be able to see where in your code the application pool is crashing. In my case, it was a function being called recursively an unlimited number of times, and that caused a stack overflow. Note: the Windows event log and the IIS logs were not helpful to diagnose the problem.

Answer 6

In addition to the steps outlined at this link from Orhan's answer, you may need to additionally remove the native module by going to IIS Manager > Server Root > Modules > Configure Native Modules. Select MfeEngine and then select Remove.