iTunes session has expired message and can't correctly login
I changed my apple password and I am now unable to fully log into my account in iTunes. The message "your itunes session has expired" keeps popping up. I enter the user and password correctly, and it takes the password but when I try and play apple music I am prompted to enter my password again? I am entering the password correctly. I am running Max Sierra and iTunes 12.8.3. I can't update beyond this. Any help would be appreciated?
iMac, macOS 10.12