Sometimes authentication fails or syncing becomes blocked for a particular email account. In this case it's very likely that their server is blocking access via the ActiveSync protocol, which is the protocol we use to sync data from various Microsoft products.
- Make sure the mobile > mobile device access menu doesn't have any quarantined devices, that mobile device provisioning is enabled, and that there aren't any device access rules in conflict with our suggested settings
- In your Exchange admin center make sure that protection > action center menu doesn't have any accounts impacted by the protection system.
- Make sure the protection > quarantine doesn't have any blocked devices
- From the user's settings page make sure that the mobile devices page allows two
python-EAS-Client 1.0types to connect.