We have Exchange 2010, and everything appears to be normal for all outlook clients except Outlook 2016.
We are able to get the client to connect normally, and it works for a few days, but every time, and after a few days (sometimes a week or a little more) the 2016 client stops being able to update the server.
Outlook 2016 still retrieves mail, but if you delete or move a message, it only happens on the client. OWA or phones never get the changes, and after some time, the change will revert when the client syncs with the server again. Same thing with calendar entries. You can update something, but it will never show up in OWA, and eventually will revert, as if you never did it.
Environment is Exchange 2010 on Server 2008R2
Windows 10 clients connected via VPN
Autoconfig passes tests
Current patches and updates on both the server and workstations.