OK so if you have access to the IIS logs in the Exchange server you should be able to get a lot of clues as noted by other users. The 1st thing to get right is make sure that you can login to the OMA (Outlook Mobile Access) URL via any browser. In our shop it's
http://domain.org/oma.
If you can't login the Exchange system admin will need to follow the steps in
http://support.microsoft.com/default.aspx?kbid=817379. We also were getting the "A System error has occurred while processing your request" error message so we followed
http://support.microsoft.com/kb/898131/ and voila OMA via a browser began to work.
Well the iPhone 3G was getting this message every time we tried to send/receive mail:
Cannot Send Mail
An error occurred while delivering this message.
So we took a look at the IIS log. Notice with the iPhone 3G user his log entry:
with SSL disabled:
2008-08-06 15:03:55 W3SVC1 10.0.x.x OPTIONS /oma/Microsoft-Server-ActiveSync - 80 someone 32.136.48.40 Apple-iPhone/502.108 200 0 0
with SSL enabled:
2008-08-06 15:05:40 W3SVC1 10.0.x.x OPTIONS /oma/Microsoft-Server-ActiveSync - 443 someone 32.136.48.40 Apple-iPhone/502.108 200 0 0
Hmm what's different from using OMA via the browser successfully?
2008-08-06 15:09:02 W3SVC1 10.0.225.241 PROPFIND /exchange-oma/someonelse/ - 80 xxx\someonelse 10.0.225.241 - 207 0 0
Yep the path is "exchange-oma" and NOT "oma". Hmmm. Lo and behold what could it be?
Well in the domain field of said iPhone 3G we had 'http://domain.org/oma' thinking, well "that's how we get in via a regular ole' web browser". Ha so much for that thinking. We took out the '/oma' and voila. Action Jackson.
Bottom line: logs are your (sys admin's) friend...