My game instance disappears after restarting the engine

I think the problem may be related to what this user comments.

I can’t see the subfolders either

I have migrated this project two times.
1-From version 4.27 to 5.0.3 version
2-From a Blueprint project to a C++ project on 5.0.3 version

So probably something went wrong in some migration process.

Does anyone know how to fix the modules?