MacBook Pro trouble signing into App Store, iMessage and iCloud New macbook and while trying to sign into the App Store, iMessage and iCloud it just loads for hours, correct email and password yet loading symbol appears and spins for hours. Any fixes??
I believe it is a problem on Apple's side. Just give it a day or two and try again.

http://www.macrumors.com/2016/03/23/mac-users-facetime-imessage-login-issues/