The iPhone message “This accessory may not be supported” can be caused by compatibility, cable, power, or connector problems. Learn what to check.
The message is about the accessory connection rather than your Apple ID. It can appear when an accessory is incompatible, damaged, not certified for the device, or unable to draw the power it needs.
A dirty or damaged connector can produce the same message as an incompatible accessory. Testing the accessory and the iPhone port separately helps narrow down the cause.