It's not letting me login into iCloud even though I have the Apple id and password. How do I fix this?

I have an Apple ID and the correct password but its not letting me login into my iCould on my MacBook Air. Every time I try to login in I always get this notification "You cannot sign in to iCloud because there was a problem verifying the identity of this Mac. Try restarting your Mac and signing in again." And I have restarted my Mac several times but I still can't login. Please help!