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Exchange Team Blog
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Configuring Teams calendar access for Exchange on-premises mailboxes

The_Exchange_Team's avatar
The_Exchange_Team
Icon for Microsoft rankMicrosoft
Jun 23, 2020
Over the last several months, we have seen many customers adopting Microsoft Teams, even if their mailboxes are still hosted in an on-premises environment. One of the common issues in this scenario i...
Updated Nov 09, 2023
Version 8.0
Calendaring
hybrid
on premises
BNalepa's avatar
BNalepa
Copper Contributor
Nov 26, 2020

This issue seems to be still existent. I have a customer with EX2019, Full classic hybrid configured, OAUTH tests pass with success both ways. All other tests (exRCA) pass as well. OWA on-line can see free/busy for on-prem mailboxes, however teams calendar app does not want to cooperate. The error we see in teams client is CalendarService: Error while fetching the meeting type None: Error {"response":{"errorCode":"ErrorNonExistentMailbox"},"status":400,"_codeEnum":0,"_code":"ErrorNonExistentMailbox","_message":"Unknown service error."}