Travel error

I keep getting a travel error when trying to go from my main menu into a level, and it says it’s bc the file is invalid for my intro, but when i change the start up map to my menu instead of my intro it gives the same error for the menu. This leads me to believe that it’s an issue with level transitioning, but i have no idea why. my levels were working as planned until today. only change i made was adding textures to maps. anyone know a fix for this error? i’ve been searching all day for a fix and nothing worked.