Fixed via changing /Config/DefaultEngine.ini
From EditorStartupMap=/Game/PingPongMap.PingPongMap
To EditorStartupMap=/Game/Maps/PingPongMap.PingPongMap
Fixed via changing /Config/DefaultEngine.ini
From EditorStartupMap=/Game/PingPongMap.PingPongMap
To EditorStartupMap=/Game/Maps/PingPongMap.PingPongMap