Good day!
We have a local installation of Exchange 2019. Services are published through the IIS ARR reverse proxy.
Everything works correctly, including OWA and the Outlook desktop client. But, at some point in time, some clients on mobile devices stop syncing. At the same time testconnectivity.microsoft.com shows that everything is ok.
Manually, this problem is solved if all the user's mobile devices are deleted via the ecp. Then, at the next synchronization, everything starts working as it should.
This affects only a part of the clients, the other part continues to work correctly. Clients with Gmail app on Android and native mailapp on iOS work without any problems.
