One quite day of less help desk tickets and my servers were humming in data center in good harmony, I have been called to check out Windows Mobile wireless email issue for a top executive who was traveling. IT was questioned why we weren’t renew the security certificates.
From the error message, It’s straight forwardly telling to correct the date and time in the mobile. But the following MSKB tells different scenario: http://support.microsoft.com/kb/927465. I was sure this KB does not apply to us, because all other Mobile devices were synchronizing without issues including my own. I am very sure of my SSL certificate is not expired.
But simple soft re-set of the device resolved the issue. I recommended to remove the battery from the device, wait for a minute and put the battery back in. So I am guessing the user was in different time zone and device was not in sync with provider’s network time. Resetting the device allowed to connect to new mobile network tower and sync the time with provider.
Along the way of digging, I found the following information which could help you.
Exchange ActiveSync Support Codes, Errors, Resolution and Cases
(same info as above, but some additions) Exchange ActiveSync Error codes and what they mean
Anand, the Architect 