You may already be part way through the recommended sequence...
Begin with a forced-restart of your iPad - as this will often clear an isolated software issue:
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.
If the problem persists after performing the restart, it may be necessary to reset your iPad settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:
How to back up your iPhone, iPad, and iPod touch - Apple Support
When you are happy to proceed, you can perform the reset from iPad settings:
Settings > General > Transfer or Reset iPad > Reset > Reset All Settings
If the problem still doesn’t clear, the next step is to reset the iPad to factory settings; do not restore from your backup when prompted:
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
The objective of restoring the iPad to factory settings alone is to eliminate the possibility of your backup restoring settings that may be the source of issues. For diagnostic purposes, initially setup the iPad "as new" without restoring your iCloud or iTunes backup.
If the problem remains unresolved, you would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively and perhaps easier, you can initiate and manage your support cases using the excellent Apple Support App. If not already installed on your iPad, the App can be downloaded from the App Store:
https://apps.apple.com/app/apple-support/id1130498044
You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad - and you can explore your available options:
Genius Bar Reservation and Apple Support Options - Apple
