Microsoft Teams Error mailbox does not exist

Copper Contributor

Hi i have a problem with my Echange 2016 CU12 Hybrid configuration. I have many accepted domains.


my on prem AD domain is ""

Exchange accepted domains : "" , ""

AD usernames example:

on prem email Address:


I configured Office 365 Hybrid ( sync users, configure exchange hybrid, configure federated domains(, , all settings is ok. But when i log in my teams(with my ----""  credentials) on calendar tab i have an error  mailbox does not exist1.PNG

7 Replies
Check the O-auth setting, you can test it at the bottom of this article and if not, get it configured:

Only thing I know to check if it's not working.

@Chris Webb  also i found this1.PNG

@Chris Webb i checked Oauth and is working 

@Ramil Memmedov 

have the same Issue. Did you solve it?

@Ramil Memmedov I have the same problem. Has anyone of you been able to solve it? I am grateful for every tip.

Is anyone able to solve this issue yet?

@Ramil Memmedovdid you find a solution on this? Or anyone?