You may need to completely sign-out from your AppleID account from iPad settings - then restart your iPad prior to signing-in again.
To sign-out from your AppleID:
Settings > [Your Name / AppleID] > Sign Out
During sign-out, you will be prompted to Keep a Local Copy of your iCloud data; accept the prompt.
When the sign-out process concludes, exit the settings App - then perform a forced restart of your iPad:
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)
Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

After restart, sign-in again to your AppleID from iPad settings.