Forum Discussion
MS Teams with Exchange On-Premises
MS Teams is unable to connect to Exchange calendar on Premises. The calendar icon is unavailable in Teams.
The mailbox is in Exchange on prem, there is a Hybrid configuration and Oauth is working.
The Calendar Sharing between On Premises and Cloud Users work.
The calendar is available in OWA.
All on prem users are affected.
Error message: "Your exchange calendar isn't set up. Talk to your admin to set up you calendar".
Exchange Server 2016 CU12
AtanasM How is the on-premises Exchange Server published to the Internet? Is Windows Server 2016+ Application Proxy used, or another reverse proxy component?
In regard to the Exchange hybrid configuration, is AutoDiscover DNS used or does the Exchange hybrid configuration use a static TargetAutodiscoverEpr?
13 Replies
HelloAtanasM !
Tried enabling Group-Writeback?
Also make sure that OAuth is set up correct
https://docs.microsoft.com/en-us/exchange/configure-oauth-authentication-between-exchange-and-exchange-online-organizations-exchange-2013-helpKR
Oliwer SjöbergHello oliwer_sundgren
I checked many times and Oauth is set up correctly.
Are you sure, that enabling Group-Writeback can solve the issue?
Thanks in advance.
HelloAtanasM !
If OAuth is set up correctly and your on-prem Exchange server(s) are published correctly towards the internet without special proxies or smarthosts. then Group writeback could be the issue here. It's worth a try 🙂
I've previously enabled Group-Writeback and got this to work.
Since you're in a hybrid, the local Exchange resources usualy needs a reference object in Active directory to route mail and work correctly.
Read this Docs article for referencehttps://docs.microsoft.com/en-us/exchange/hybrid-deployment/set-up-office-365-groups
Kind Regards
Oliwer sjöberg
AtanasM Did you check the external authentication methods on the AutoDiscover virtual directory?
It seems that Microsoft Teams cannot fetch AutoD version 2 data from your on-premises Exchange Servers. Are all Exchange virtual directories published to the Internet?
ThomasStensitzki-MVP how to check the external authentication methods on the AutoDiscover virtual directory? Could you send me a guideline?
