Website is continuously loading without any errors or fails with 500 - Internal Server Error after long time

Symptoms

• Website is loading continuously without showing any errors.
• After huge amount of time, loading can fall with the following error:

  CONFIG_TEXT: 500 - Internal Server Error

• No other errors can be observed.

Cause

Application Pool misconfiguration that leads to inability to spawn the worker process.

Resolution

It is required to re-create the application pool and the site in IIS.

1. Log into the server via RDP.

2. Identify what Application Pool is the website assigned to via IIS > Sites > example.com > View Applications > Application Pool:
   

3. Remove the site from IIS by right click on it and press Remove.

   Warning: in case the site was using plesk(default) application pool, skip step 4 and proceed with step 5.

4. Remove the application pool that was identified on step 2 via IIS > Application Pools > example.com(domain).
5. Re-create the site and application pool, on Plesk server it is possible with the following command executed via the command line:

   C:\> plesk repair web example.com