Software can be stubborn. If the Rockstar Games Launcher doesn't have the "permission" to talk to your hard drive, it simply gives up.
If you’re stuck in this digital purgatory, here is the "story" of how I broke through the wall and got back into the game. Chapter 1: The Ghost in the Files how-to-fix-social-club-login-error
The most common villain in this story is a corrupted local profile. Sometimes the Social Club just forgets who you are. Software can be stubborn