TravelFailure: InvalidURL when leave game back to main menu

I pretty much replicated the MultiplayerShootout example of the UE4 engine in my project an got everything to work except the “leave game” mechanism, where the session is destroyed and the main menu level is opened again, which is not working in my project as well as in the MultiplayerShootout example itself. The problem seems to be the OpenLevel function. When i try to reload the MP_Level1, it works, but when i try to open the MainMenu level, running it in the Editor, it says:

Warning TravelFailure: InvalidURL, Reason for Failure: ‘Invalid URL: /Game/MyGame/Maps/MP_MainMenu’. Shutting down PIE.

in the log, which seems to be a known issue. But even when i package the game it is not workin and displaying the failure type of the event TravelError it says “ClientTravelFailure”, “InvalidURL”. I searched for some information about it here and on other boards but found no working solution.

Can anyone give me a hint?

The complete log of the packaged version is attached. The interesting lines are starting at line number 277:

[2016.08.10-22.11.21:260][335]LogPackageName: SearchForPackageOnDisk took   0.158s, but failed to resolve MainMenu.umap.
[2016.08.10-22.11.21:260][335]LogNet: Browse: /Game/51_Multiplayer_mit_GunAndShield_kombinieren/Maps/MP_MainMenu
[2016.08.10-22.11.21:260][335]LogNet:Warning: Travel Failure: [InvalidURL]: Invalid URL: /Game/51_Multiplayer_mit_GunAndShield_kombinieren/Maps/MP_MainMenu
[2016.08.10-22.11.21:260][335]LogNet: TravelFailure: InvalidURL, Reason for Failure: 'Invalid URL: /Game/51_Multiplayer_mit_GunAndShield_kombinieren/Maps/MP_MainMenu'
[2016.08.10-22.11.21:260][335]LogBlueprintUserMessages: [MP_Steam_GameInstance_C_0] Error traveling maps due to: InvalidURL


Well what you need to do to leave game while youre in a Session,
On Click (Leave Game) - Save Game To Slot- Get Player Controller - Cast to GamePlayPlayerController - Get a Reference to GameInfo - Destroy Session Caller - Remove All Widgets - Open Level (MainMenu) Screenshot - 01b9af92a760e4b04d13158a3c91ba66 - Gyazo

Make Sure your MainMenu is Typed correctly in the Open Level