Exchange (OWA) CAS crashes with 503 error - again

Sun, 18 Sep 2011 12:22:46 +0000

This just started happening again, with these errors appearing in the event viewer:

Log Name: System
Source: Microsoft-Windows-WAS
Date: 9/18/2011 11:16:33 AM
Event ID: 5011
Task Category: None
Level: Warning
Keywords: Classic
User: N/A
Computer: exch2010fe1
Description:
A process serving application pool 'MSExchangeOWAAppPool' suffered a
fatal communication error with the Windows Process Activation Service.
The process id was '3760'. The data field contains the error number.

Log Name: System Source: Microsoft-Windows-WAS Date: 9/17/2011 6:47:07 AM Event ID: 5009 Task Category: None Level: Warning Keywords: Classic User: N/A Computer: exch2010fe1 Description: A process serving application pool ‘MSExchangeOWAAppPool’ terminated unexpectedly. The process id was ‘3108’. The process exit code was ‘0x800703e9’.

Exchange CAS crashes, users get 503 when accessing OWA... but ActiveSync works

Mon, 17 Jan 2011 19:09:15 +0000

Since migrating to Exchange 2010, every couple of weeks it looks like IIS crashes on the CAS. Going to the OWA URL in a browser would yield a 503 error. Strangely enough, ActiveSync worked fine (though Outlook Anywhere over HTTPS didn’t). Rebooting the CAS resolved the issue.

This is what the logs show (Website Pulse reported the outage around 11:45):

Information	1/16/2011 11:59	EventLog	6013	None	The system uptime is 1726976 seconds.
Error	1/16/2011 11:43	Microsoft-Windows-WAS	5002	None	Application pool 'MSExchangeOWAAppPool' is being automatically disabled due to a series of failures in the process(es) serving that application pool.
Warning	1/16/2011 11:43	Microsoft-Windows-WAS	5011	None	A process serving application pool 'MSExchangeOWAAppPool' suffered a fatal communication error with the Windows Process Activation Service. The process id was '13180'. The data field contains the error number.
Warning	1/16/2011 11:43	Microsoft-Windows-WAS	5011	None	A process serving application pool 'MSExchangeOWAAppPool' suffered a fatal communication error with the Windows Process Activation Service. The process id was '12856'. The data field contains the error number.
Warning	1/16/2011 11:42	Microsoft-Windows-WAS	5011	None	A process serving application pool 'MSExchangeOWAAppPool' suffered a fatal communication error with the Windows Process Activation Service. The process id was '15328'. The data field contains the error number.
Warning	1/16/2011 11:41	Microsoft-Windows-WAS	5011	None	A process serving application pool 'MSExchangeOWAAppPool' suffered a fatal communication error with the Windows Process Activation Service. The process id was '11724'. The data field contains the error number.
Warning	1/16/2011 11:41	Microsoft-Windows-WAS	5009	None	A process serving application pool 'MSExchangeOWAAppPool' terminated unexpectedly. The process id was '15868'. The process exit code was '0x800703e9'.
Information	1/16/2011 11:21	Service Control Manager	7036	None	The WinHTTP Web Proxy Auto-Discovery Service service entered the stopped state.

This happened before we had any antivirus on the machine (antivirus has been suggested as a culprit). The machine is Win 2008r2 x64 with all updates running Exchange 2010 with all updates.

503 on Evan Hoffman

Exchange (OWA) CAS crashes with 503 error - again

Exchange CAS crashes, users get 503 when accessing OWA... but ActiveSync works