my ipad has a box saying Accessory not Supported csnnot shut off my ipad also

See >>> If you see an ‘Accessory may not be supported’ alert - Apple Support

If you are using a Magic or Smart (folio) keyboard, the alert is typical of either a bad connection via the Smart connector, or a faulty keyboard. The electrical connections that pass though the flexible fabric hinges have been known to fracture - this usually resulting in errors and/or the on-screen notification that you see. 

As a first step, remove the iPad from the Magic/Smart Keyboard - and carefully/gently clean the smart connector contacts on both the iPad and keyboard with a soft pencil eraser (a drafting-film eraser is ideal). Ensure that the contacts on both iPad and keyboard are dirt and dust free - and all debris from the eraser have been removed - before reconnecting the two.

If the iPad is unresponsive while removed from the Keyboard, perform a forced restart:

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:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. 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.

The Magic/Smart keyboard itself is not repairable. If the keyboard has failed, the only remedy is replacement.

If you need assistance with the keyboard or your iPad, you can contact Apple Support using the Support link at top-right or bottom left of this page. Alternatively, you can initiate a support case using the excellent Apple Support App. If not already installed on your device, the App can be downloaded from the App Store:

https://apps.apple.com/gb/app/apple-support/id1130498044

A further alternative is to visit the Genius Bar at your local Apple Store, where the technicians will be delighted to assist. When visiting the Genius Bar, a reservation is recommended:

Genius Bar Reservation and Apple Support Options - Apple

You’re very welcome. I’m delighted that the problem has been successfully resolved.