External access between organizations




We are managing multiple Office 365 tenants and some are using Teams.


I would like to connect 2 of these organizations so they can chat together and be added to common teams but I'm struggling to do that.


I've followed this guide : https://docs.microsoft.com/en-us/microsoftteams/let-your-teams-users-communicate-with-other-people so I've configured the external access but it still not working, users can't chat with external people. I've also enabled guest access on both tenants but nothing changed.


The operation seems easy but it's not working... I would appreciate if someone could help me, thanks.

21 Replies

@Thomas Binder So you took it offline and we never knew what the solution is.


I have whitelisted domains on both sides, but some Teams users are getting my messages but others are not.

I keep getting this error when trying to send something to an external user: "This user is unavailable. We've sent an email instead."


Please advise on what the solution is.

IS there a solution to this we are experiencing the same issue?