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A note on connectivity issues

If you see black videos from peers or the connection state displayed ontop of those videos either hangs in Connecting to peer... or changes to Connection failed, a direct peer-to-peer connection could not be established.
This typically means that a TURN server is required. This tutorial explains the problem. You can check if those peers can connect each other on which runs a TURN server.
Want to know more about how some of these features work? Check the documentation