Conversations involving multiple participants, allowing collaboration and information sharing in Teams
Hi testu222,
My name is Didi. I'm happy to help you today.
It is possible to chat with folks outside our domain as long as external access is enabled from the Teams admin center. Could you confirm such a setting as well as if the user's domain is blocked?
You may see the article for the complete guide:
https://docs.microsoft.com/en-us/microsoftteams...
Best regards,