SteamAppId gets ignored, launches always as SpaceWar

Hello,

I tried to set up a game for Steam and it’s only partly working. I followed the Tutorial: Online Subsystem Steam | Unreal Engine Documentation

It worked for my older game which I released and it is “working” now with a very strange artefact. I can set the SteamDevAppId in the config to my AppID but the game always launches as SpaceWars. Tried it with the same config from my older game with the same old AppId and it still won’t work while it’s working on the old game on UE 4.16.

Any idea or fix?
Thank you!