Communication beatween two organization

Occasional Visitor

Hello, we have two organization with mails: and second one, and we would like to let people from second organization to communicate with first. I'm the owner of first organization. I added some people from second  as guest and they confirmed invitation, I also check option to communicate with other teams (on my site), and added to trusted domain.  What should be done to let users from second company communicate with first? Second also need to check option to let communicate with others teams?

When user want to search Externally, they can see that they cannot talk to each other.

1 Reply
It could mean a few things:

- Federation is not properly setup. In Teams Admin center you can configure if you allow communication with all domains, allow or block specific domains. Please make sure this is setup correctly. You can find more info at

- Check the Trams coexistence policies. I’ve seen something similar before where they were set incorrectly on one of the tenants. Preferably both should be Teams Only if there is no Skype for Business usage anymore.