Question : Exchange Front-End HTTP/1.1 503 Service Unavailable

I'm running Windows Server 2003 Enterprise Edition on the back end, with Exchange 2003 (Clustered).  On the front end I'm running Windows Server 2003 Standard Edition, with Exchange 2003.  For OWA access, I'm requireing SSL.  As of yesterday, everytime you try to hit OWA, you get the following error "HTTP/1.1 503 Service Unavailable", sometimes you get prompted for a certificate, and sometimes you don't.  These are the only errors I've been able to find so far.

Back-End:

Event Type:      Error
Event Source:      MSExchangeSA
Event Category:      Monitoring
Event ID:      9100
Date:            3/22/2005
Time:            7:34:30 AM
User:            N/A
Computer:      BackEndServerName
Description:
The MAD Monitoring thread was unable to read the queue information, error '0x800706b5'.

Front-End:
Event Type:      Error
Event Source:      MSExchangeES
Event Category:      General
Event ID:      5
Date:            3/22/2005
Time:            7:37:40 AM
User:            N/A
Computer:      FrontEndServerName
Description:
An unexpected MAPI error occurred.  Error returned was [0x80004005].

Event Type:      Error
Event Source:      Schannel
Event Category:      None
Event ID:      36884
Date:            3/21/2005
Time:            4:12:43 PM
User:            N/A
Computer:      FrontEndServerName
Description:
The certificate received from the remote server does not contain the expected name. It is therefore not possible to determine whether we are connecting to the  correct server. The server name we were expecting is FrontEndServerName.mydomain.com. The SSL connection request has  failed. The attached data contains the server certificate.

Everything was working fine until late Sunday night, or early Monday morning.  I've found a few KB articles that reference the Event ID:5 error, but after reading it I'm not really sure if it applies.

Any help that someone could provide would be greatly appreciated.

Roland Serman
Network Manager
Cherokee County Schools

Answer : Exchange Front-End HTTP/1.1 503 Service Unavailable

The exchange event service is a worker service and is related to Exchange 5.5 domains. This service is not necessary in your configuration, so you can ignore that error.

Did you adjust the permissions in IIS to reflect those above? I noticed some differences?