Hey Hevedy,
If you are attempting to pair a base class with a non-base class (such as, say, using a Game Mode and a Game State Base), this will not work. These are only meant to be used in conjunction with each other. So, if you are using one Base class (GameModeBase) the Game State class must match (GameStateBase). If it does not, this can cause quite a few issues, including certain functions and events not being called in your blueprints.
If this is not the issue that you’re experiencing, please explain clearly what the issue is, and provide a detailed list of steps that I can use to reproduce the issue on my end.
Have a great day