IIS stopped and error message "HTTP Error 503. The service is unavailable"

Question

I have a problem with IIS that I cannot resolve.

Given that:

• the Windows Event Viewer doesn't detect any application level errors
• with debugdiag two rules are active for monitoring exceptions (of the stackoverflow type) and on excessive use of resources and have not performed any dumps

Quite randomly ( infrequently ) the application responds to the front-end with the error message " HTTP Error 503. The service is unavailable. ".

Trying to reboot from the prompt via the iisreset command fails and remains stopped and trying to reboot directly from IIS I get the following error message " Web Publishing Service (W3SVC) stopped. Websites cannot be started if the Web Publishing Service (W3SVC) is not running ";

See the following link:

enter image description here

To restart the application pool the only solution is to kill the process and then restart it.

What could it depend on? Could it be some other service that can give IIS problems?

I hope someone can give me some useful information.

Thanks in advance.

Answer 1

I think you have two questions:

1. How you can detect the root cause of 503 error

503 error => common cause is the application crash. You should set debugdiag rules to collect dump for application crash and analysis the dump for the crash reason.

2. What the dependencies are for W3SVC and how we can solve this "not running" issue

Dependencies are:

• Windows Process Activation Service
• Remote Procedure Call (RPC)
• DCOM Server Process Launcher
• RPC Endpoint Mapper

You can refer to this answer about how to solve "w3svc service is not running error".

IIS w3svc error

Hope helps.