Close you project.
Open you project folder and delete - Binaries. Build. Intermediate. Saved. (its save all you lvls and code but only delete old build.)
Open you project and reconfigurate again you Project settings.
If you not sure in it, create new project and in new project folder add from old project folder - Content. Config.
And again reconfigurete.
If it dosnt help try to manualy set SDK and NDJ and JDK to engine. Or swith to new version of engine and create new project in it.
