A process serving application pool 'Classic .NET AppPool' suffered a fatal communication error with the Windows Process Activation Service

Question

I am running an ASP.NET 3.5 web application on IIS 7 on Windows Server 2008.

I received the following error earlier this afternoon:

HTTP Error 503. The

Answer 1

If you are using NServiceBus make sure whatever account the application pool is running under has permissions to read off of the message queue.

NServiceBus runs a background task on application startup that timesout after 10 seconds, causing the w3wp process to be killed if it can't read from the queue. After n (default of 5) w3wp crashes Rapid-Fail Protection kicks in and stops the application pool.

http://blog.jonathanoliver.com/2010/11/nservicebus-w3wp-exe-processes-crashing/