SQL Server stops working due to specific sites IIS AppPool crashes it

Question

I have a server with multiple sites and I have experienced the following Event Viewer Error:

Server local connection provider has stopped listening on [ \\.\\pipe\\SQLLocal\\MSSQLSERVER ] due to a failure. Error: 0xe8, state: 4. The server will automatically attempt to re-establish listening.

This error occurs directly after one of the sites on my server generates a Warning in the Event Viewer:

Event code: 3005 
Event message: An unhandled exception has occurred. 
Event time: 8/4/2017 2:33:05 PM 
Event time (UTC): 8/4/2017 1:33:05 PM 
Event ID: 8fe181c1dde54b359dd40f946cd6d1ae 
Event sequence: 15 
Event occurrence: 1 
Event detail code: 0 

Application information: 
    Application domain: /LM/W3SVC/11/ROOT-1-131463267483252556 
    Trust level: Full 
    Application Virtual Path: / 
    Application Path: C:\Hosting\www.testsite.com\ 
    Machine name: S1 

Process information: 
    Process ID: 5856 
    Process name: w3wp.exe 
    Account name: IIS APPPOOL\www.testsite.com 

Exception information: 
    Exception type: Win32Exception 
    Exception message: The wait operation timed out



Request information: 
    Request URL: http://www.testsite.com/en-ie/about 
    Request path: /en-ie/about 
    User host address: 90.100.170.80 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: IIS APPPOOL\www.testsite.com 

Thread information: 
    Thread ID: 22 
    Thread account name: IIS APPPOOL\www.testsite.com 
    Is impersonating: False 
    Stack trace: 

Custom event details: 

I know that if I turn off 'testsite' in IIS then my server works fine for all other sites. Any idea is it something gone wrong with the AppPool? Something to do in IIS? I am not encountering this problem with this site locally in IIS.

Answer 1

I compared site with others on same server and found its App Pool had duplicate applications assigned. I removed one and problem was resolved.

Still seeing the following error in relation to that same site though:

Message: Unable to find assembly 'Lucene.Net, Version=3.0.3.0, Culture=neutral, PublicKeyToken=85089178b9ac3181'.

This may or may not have been invoved with the initial db overloading as the EvenLog table was quite large with errors from Lucene (from DNN module 'SearchBoost').