Server Travel Command Crash

Hello everyone, I’m currently following Unreal Engine’s Blueprint Multiplayer Tutorials and have got to episode 15 where they integrated a ‘launching the game’ function. They do this using the command ‘servertravel’. For some reason, whenever I try to call the server travel command the game always crashes. I’ve attached an image to show what I’ve done. Also, I’ve checked the names and tried with other levels, and none of them work.

Thanks in advance!