[Unreal] Unable to join session

I encountered the issue of being unable to join a session in 4.21 too. In 4.20 it works fine, when the ini is set up properly. In 4.21 the JoinSession node returns that joining the session was successful, but the client travel function doesn't seem to be processing properly. The map does not instantly reload onto the server's map. It takes a good while, then the client restarts with the correct session still active, but the server never registers that the client joined. Both then are in the same correct session and the session player count is 2 but they are not in the same game/map.

The project is C++ and using Epics 4.21.2. When trying to build the Oculus version, it compiles properly, but on trying to open the project files it requires to rebuild the engine again and ends with an error, that I couldn't resolve. So I can only test and open it with Epics 4.21.2 so far.