Calendar not available for OnPremise accounts


Hello everyone.


I have this issue in my Teams deployment where Calendar app is not available for OnPremise accounts, only for accounts made online. AD is synced with Azure.


What I mean about that is some time ago we had SFB deployed in the infrastructure. As it was not fully working I simply deleted it. Issues started with the old accounts as the external connectivity did not work with those accounts since there were still left Skype for Business attributes assigned to them, we cleared those. Since then that has been resolved.


But now I don't seem to find the solution how to enable calendar functionality to those accounts. Where should I dig further?


I use Office 365 E3 licenses, AD synced with Azure and Exchange 2016 CU7. Only on-premise accounts are used with on-premise mailboxes. Exchange server is on-premise, not configured as Hybrid.




3 Replies

Bump with updated description @James1 

@James1 Update: Ive updated the Exchange server to the newest CU. The issue still persists. 

However the Exchange is fully on-premise, the hybrid is not configured.

best response confirmed by James1 (Contributor)

@James1 Finally found a solution.


In order to get the calendar functionality in Teams it is needed to create a Hybrid connection between your on-premise Exchange server and Azure (note that trusted SSL is then needed). 


If that still does not fix the issue, try to clear all msRTC attributes from onpremise AD accounts, then resync. 


Those two actions fixed the issue for me, but note that I had onpremise Exchange2016 with latest updates and incorrectly decommissioned Skype for Business server, thats why msRTC attributes had to be cleared.