Multiplayer LAN client kicked off when starting session

So I was following the Unreal official tutorial series on YouTube( Blueprint Multiplayer | v4.11 | Unreal Engine - YouTube ) and I reached the last moment of making the host start a session after clients join and pick their characters. But the problem occurs here: the host enters the main map without any problems, but all of the clients get kicked off, into their main menu screen.
I have checked pretty much the entirety of the blueprints and made sure there were no differences with the tutorials shown, but I could not find any that may present problems.
Please do note that I have altered my blueprints quite a bit, such as omitting the chat feature, the map image, game settings menu, character image, and removing the “disable characters that have already been selected” device that was implemented in the video, but that I have made sure not to affect the core systems(esp. the multiplayer systems).
Did I do something wrong? Were there parts that I shouldn’t have modified? Any help would be appreciated.