This Accessory May Not Be Supported. Is the phone or cable bad? Apple wants you to buy their data cables.
My iPhone will charge from my computer, my iPad will not because there is not enough power. Note that if you get another error message like "This cable or accessory is not certified and may not work reliably with this iPhone[iPad]", you can resolve it by using these. Some iPhone/iPad users are likely to encounter the error message "this accessory may not be supported" while trying to charge their phones or use headphones on them.
For iPhone users, "This accessory may not be supported" error has to be the most frustrating one.
This accessory may not be supported.
One of them is getting the "this accessory may not be supported" message when trying to plug the charger into the device. You can try testing the iPad once again to see if the Smart Keyboard keeps showing the "This accessory is not supported by this device" error. If so, you can repair the operating system using Tenorshare ReiBoot.