Mobile endless loading while joining UEFN session

Summary

If you wish to playtest your UEFN game by launching a session and having your mobile phone join as a second player, there is an issue where the phone player gets stuck in endless loading. The phone user has to close Fortnite on their phone, launch it again, join the party and join the session again, only then the phone player gets inside the game.
It’s an issue which kills work flow, because it takes multiple minutes to get a phone into a UEFN session to test a game mechanic out.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Collaboration

Steps to Reproduce

Open any project on UEFN and launch session. Once the session in loaded, have a second account on a phone device, which is in the same UEFN team, join the session. The phone device will be stuck inside the loading screen while trying to join the UEFN session forever. Afterwards close Fortnite on your mobile phone, open it again and join the UEFN Session again, this time it works fine.

Expected Result

The phone account should join the session the first time it attempts to join it, without being stuck in an endless loading screen.

Observed Result

The phone account gets stuck in the loading screen forever.

Platform(s)

Mobile Phone (android and iOS).