Web App returning Https Server Errors resulting in backend call failure

Question

Setup runbook to restart app service when a threshold for Http server errors is hit, but not always bringing service back up. Either returns a 500 error of "backend call failure". Ran through troubleshooter and it returned this:

"Errors routing request to container

The application container returned a Connection Refused error. This typically happens if some resource limit is being hit within the application container which is forcing the connections to be refused. Please check the application container code and underlying frameworks used to identify possible scenarios where the app could return 'Connection Refused' errors."