iTunes constantly ask me to sign in
iTunes constantly ask me to sign in. Even when I sign in it will ask me to sign in right away again. The only thing that stops it is to Force Quit. The cycle starts again later. The same thing happens on my iPhone and iPad. It accepts the password that I enter. Also in the in my Download Activity button in iTunes it says it can't make my iTunes Music Library. I am not sure why this is happening.
iMac (27-inch, Late 2012), macOS Sierra (10.12)