Did you have an old player character or something that you deleted?
If you pressed “force delete” its essentially just broken unless you understand pointers on a level that you can open open all the files in c++ and fix them
If you didnt do that, good news you should just be able to right click the node and choose refresh or delete it and put the castto node back in place
If you did and arent an expert on c++, pointers and redirectors then bad news its easier to make a whole new project and copy everything over