I had the same issue with my exchange email. Was using the MobileIron program with Email+.
IT guy at work said that something in the lollipop upgrade deleted native exchange accessibility... At least with MobileIron. He had the same issue as well. He tried a few alternatives and finally had me load up the Outlook app.
So far so good...
My only complaint is I can't find a decent widget... The outlook one is (in my opinion) ugly. . All the other widgets I have tried so far haven't been able to even "see" my exchange calendar.
But at least the functionality has been restored.
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