Federation invalid room [undefined]

Hi we’re trying to set up a federation between 2 rocket chat servers (different domains)
The records are ok, the test setup button does work without errors on both sides.
we can successfully search for a user through the “external users” search box, but if we click on the user we get an error Invalid Room [undefined] , in the log we see"API ➔ debug get federation.users.getByUsername threw an error: TypeError: Cannot read property ‘0’ of undefined"

  • Version of Rocket.Chat Server: 3.9.7
  • Operating System: Ubuntu 18.04.3
  • Deployment Method: snap
  • Number of Running Instances: 1
  • DB Replicaset Oplog:
  • NodeJS Version: v12.18.4
  • MongoDB Version: 3.6.14
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