Server crashes after Open Level

I’m building multiplayer game.

I want to add “Return To Main Menu” button in game menu. If it would be clicked by client, it should go to Main Menu alone (that part works), If it would be clicked by server, it should stop game and all players should go to MainMenu.

When I click the Quit button on client, it works as it should.
When I click the Quit button on the server side, it crashes showing this window:

The Blueprint that I used to quit to MainMenu looks like that:

68621-zrzut+ekranu+2015-11-29+12.01.17.png

I’m creating server by creating lobby where players can wait for game start first:

Then in lobby I’m opening the level with following BP:

If all players are ready, it uses ServerTravel to open level.

** BUMP **

Closing just to be closed. It was widget without a correct owner if I remember correctly BTW.