Edward is having trouble logging into iCloud on his Mac. It just "beachballs" and then returns to the login screen. He can log in using just about every other device he has, but not his Mac. He's using the latest version of BigSur, too. What gives? Leo says you can try signing out and then sign back in again from another device to see if it clears out. You can also try booting into safe mode.
Leo suspects, though, that there's a security app on Edward's Mac blocking the login. Malware Bytes, for instance, will do this.