Can_instance: Cannot instance script because the associated class could not be found

Godot Version

v4.2.1.stable.mono.official [b09f793f5]

Question

I’ve been working on a project for a few weeks, until it suddenly broke. When I open it the window completely freezes, nothing loads, and I can’t do anything, not even close it via the task manager.

Since I don’t know a way to fix it, I just decided to create a new project and copy all the files.

This works, but now I get the titular error for all of the scripts. The class names match the file names, and the script paths seem to be correct also.

How do I fix it? I’m using C# by the way.