I need some help with a bug, anyone knows how to fix it?

So my friend started a dedicated server and I was playing with him, he is kinda new, and it got him really into the game, but some weird bug happened, where he can't open some menus, because it crashes his game, and the same happens if he tries in single player.
Some menus he can't enter are, the tech upgrade, to enter the gate, and other shops from the outpost.
We stopped after that, because he wouldn't be able to play anymore.
If anyone knows how to solve I'm sure it will help all the comunity