Error Message

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

Do you use an Apple Smart keyboard? This alert is typical of a faulty folio keyboard. The electrical connections that pass though the flexible fabric hinges typically fracture - this usually resulting in errors and/or the on-screen notification that you see. 

The Smart folio keyboard itself is not repairable. The only remedy is replacement of the keyboard. As you appear to be within your one-year limited warranty, you need to contact Apple Support or your retailer.

You will find the Get Support link at top-right 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:

https://www.apple.com/uk/retail/geniusbar/

Use a strong flashlight and see if you can see any dust, dirt, lint or other obstructions in the lightning port. It may be getting some connections there. If you see anything, do not try blowing in there, use a non-conductive device, such as a wooden toothpick to try and remove it.

What are you doing when you see this? Were you trying to connect something to the lightning port?