Cannot open source file "PaperCharacter.h" after merging branches on GitHub

Hello! I seem to be getting a bizzare error after merging some branches in my repository. I wanted to test how well will the implemented features of another branch will work and I got an error looking like this:
It says: “cannot open source file “PaperCharacter.h””. I’ve already tried rebuilding the visual studio source files and modules. Reverting to previous commit doesn’t seem to help. I’m really desperate as this is weeks of work. Is there any way to fix this?