My organization has just flipped the switch to go into Teams-Only Mode along with another O365 Tenant which was planned out perfectly.
Today we have done this & I can communicate via Chat/Call with the 3rd Party Tenant, however I cannot share files or perform screen shares. We also do not appear to be able to get Presence from these External Tenants.
When can we expect P2P File Sharing & Screen Sharing Capabilities. We had this in SfB as a native feature.
Roger Capone commented
We're having the same problem. Basic external federation features that just worked in Skype for Business are broken in Teams.