We recently did an Exchange migration from 2007 to 2013 and everything seemed to be working fine. I had Exchange 2013 running for a week with no one having issues and shutdown the 2007 server for a day to ensure nothing was relying on it. I uninstalled 2007 yesterday and everything seemed to be okay.
However, some iPhones are having issues connecting to Exchange from their phones now. They get a message that says "Cannot Get Mail - The connection to the server failed."
This is only apparently happening on a few iPhones in our organization and people with Android are having no issues. On one of the devices I was able to attach my email to their phone and it worked but won't work with their credentials. I'm at a loss as to what could be causing this.
I have already tried toggling 'Exchange ActiveSync', removed the mobile device from their Exchange profile, and made sure they have Inherited Permissions in AD. None of which are helping. I have also Reset Network Settings on the iPhone and tried removing/adding the account again with no success either.