Chatting with cross-tenant synchronization

Hi svhelden,

the behavior you're experiencing is expected with cross-tenant synchronization in Microsoft Teams. To ensure both users can see chat messages, it's best for UserA to initiate chats with "UserB (External)" (the home tenant account) and for UserB to do the same with "UserA (External)."

This way, messages will be visible in both tenants. There is no direct way to sync chat messages between synchronized accounts in different tenants without manual switching.

Here are some additional details about cross-tenant synchronization in Microsoft Teams:

• Cross-tenant synchronization is a one-way process. This means that users from the source tenant are synchronized to the target tenant, but not the other way around.
• Synchronized users have their own account in the target tenant. This means that they have their own profile, mailbox, and Teams chat history.
• Synchronized users can access Teams in the target tenant. They can chat with other users, join teams, and participate in meetings.
• Synchronized users cannot access other Microsoft 365 services in the target tenant. This is because they are not considered to be full members of the target tenant.

For more information on cross-tenant synchronization in Microsoft Teams, please refer to the following links:

• Cross-tenant synchronization in Microsoft Teams: https://learn.microsoft.com/en-us/entra/identity/multi-tenant-organizations/cross-tenant-synchronization-configure
• What is cross-tenant synchronization in Microsoft Entra ID?: https://learn.microsoft.com/en-us/entra/identity/multi-tenant-organizations/cross-tenant-synchronization-overview