I have two users that as of Thursday have stopped syncing via the iPhone. I have completely resetup the ZMM app and allowed the Mobility profile to reconfigure on the phone. The system configures correctly and downloads mail all the way up to Thursday and stops. I can see the sync times on the server update and all other devices, including mine, sync as expected. It is just these two devices.

Any ideas on what to check next or what might be going on?

ZMM 3.2.1