We're running Exchange 2007 on a box with Small Business Server 2008. A user's AD account's password expired yesterday, so he reset it in the morning. He uses Exchange ActiveSync on his iPhone - he was still able to access his account on his phone without entering his new password, for about eight hours after changing it.
This morning, he was no longer able to access his email on his iPhone with either the new password or the old one. We reset his password again, and neither the original, yesterday's, or today's new password will allow him to log in from his phone. The phone has 3G and wifi connectivity.
Is there a delay in password synchronization between Exchange and Active Directory? Is there some explanation for this behavior?