Can't get iTunes to work, says it needs Authorization....

I am trying to play iTunes on my mac, which is the only computer on my list of authorized devices. It keeps saying i need to authorize this computer first. When I go to Account>Authorization... it says I have too many devices. My Mac is up to date and I have shut down and restarted iTunes. The only other devices I have on my account is my watch, my phone, and my ipad.