So recently we've rolled out an Exchange 2010 cluster at one of our larger clients and for the most part its gone smoothly but it seemed that slowly more and more iPhone users were complaining their iPhones couldn't send mail.
The issue seemed really intermittent and difficult to reproduce, but certainly getting steadily worse.
We didn't realize it at the time but we were rolling out Exchange 2010 at about the same time Apple released iOS4.
Although you won't find any official statements from Apple that the problem even exists with iOS4 it seems they kind of borked their implementation of Exchange Activesync 14 in iOS4. EAS14 implements some fancy new "smart" features that I'm assuming Apple tried to take advantage of.
This problem manifests itself as users that can't send emails from their exchange account, it just sits there and spins and spins forever and as rapidly decreasing battery life on iPhones.
If you check out the Apple message boards you'll find a dozen or so pages full of people screaming about this problem and if you look carefully you'll find a link to JimGoings.com where he posts a .mobileconfig file that essentially disables support for Activesync 14 (in case you're wondering Microsoft skipped version 13... you know, bad luck).
We have rolled this out to around 100 users and it seems to be the miracle cure for iOS4.
Check it out! BlackListExchange2010.mobileconfig
