Hi, I'm running Exchange SP2 on Server 2008 SP2. When I try to browse OWA or localhost I get a message saying HTTP Error 503. The service is unavailable I have found that a number Application Pools despite restarting continue to fail with error messages Event ID 5002 Application pool 'MSExchangeServicesAppPool' is being automatically disabled due to a series of failures in the process(es) serving that application pool. Event ID 5139 A listener channel for protocol 'http' in worker process '4880' serving application pool 'MSExchangeServicesAppPool' reported a listener channel failure. The data field contains the error number. Event ID 5139 A listener channel for protocol 'http' in worker process '4784' serving application pool 'MSExchangeServicesAppPool' reported a listener channel failure. The data field contains the error number. The KB articles I have found whislt trying to troubleshoot this simply say to restart App Pools. I need to find why the are failing and remedy it. any suggestions welcomed. Thanks in Advance, Adam

What version of Exchange? http://www.lmbtfy.com/?q=exchange+owa+503 Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Hello, The two errors are generated by windows system. And there are many reasons which may cause the error. This is exchange forum, I can help you to solve issue related to exchange server. Please check if there is any error related to exchange server in application log. Please run EXBPA against exchange server health check.Cara Chen TechNet Community Support

Hi Guys, Thank you for your replies. I ended up logging a case with Microsoft Support. Thanks, adam