Apple ID has been disabled

If your Apple ID is locked or disabled - https://support.apple.com/HT204106 - "If you or someone else enters your password, security questions, or other account information incorrectly too many times, your Apple ID automatically locks to protect your security and you can't sign in to any Apple services. You can unlock your Apple ID after you verify your identity."

https://iforgot.apple.com/password/verify/appleid - "You’ve come to the right place to reset a forgotten password, unlock your account, or recover an Apple ID. "

What to do after [or before] you change your Apple ID email address or password - https://support.apple.com/HT204071 - "After you change your Apple ID email address or password, you might need to update your sign-in information with any Apple services you're using." - Or if you're seeing persistent disabled messages or repeated requests for the password to your previous Apple ID.

If you cannot resolve it yourself:

Contact Apple for help with Apple ID account security - https://support.apple.com/HT204169

More unusually an account may be disabled because you owe money on a purchase and have stopped payment through a card. --> iTunes - Official Apple Support - https://support.apple.com/itunes