Multiplayer Possession Inconsistent

I currently have a project that’s multiplayer setup is based off of Unreal’s YouTube tutorial on Blueprint Multiplayer.

At the moment, with three different machines, going from the lobby to the “arena” is very inconsistent in terms of possession. At times, both players and server will have possession of their characters, other times only the server will have possession. On rare occasions, sessions cannot be found.

All players enter this new map via servertravel, and when the clients do not have control of their character, they can still see the Server character moving around.

When a player does not have possession, they do not have access to any inputs - - mouse and hotkeys.

From Machine A to Machine B, the success rate may be 50%, but from Machine B to Machine C, the success rate may be 33%.

I am using the Steam Online Subsystem to test this, with all three machines pulling from the same repository.

Thanks for reading.

I’ve got the same problem.

Also, I have an event (executes on owning client, reliable) in gameplay player controller, wich remove loading screen widget. I call it from my gameplay GameMode on the server. And it works.
But possession does not work. The server thinks all players control their pawns, but clients can do nothing and they are located somewhere around (0, 0, 0). Clients see all world changes, but in some seconds they get black screen.

This is not dedicated server. Seamless travel is switched on. I use server travel consol command. Also, I test it with packaged game on Steam with different computers and Steam accounts.

When I tested multiplayer with no lobby and no server travel, all worked fine, but after server travel there is a problem with possession clients. Server player works good.

Unreal Engine 4.16.3. Steamworks sdk 1.40. Plugin: Advanced Steam Session 1.9.