Update your iphone to the latest ios. After that you need to turn off the device by pressing the sleep and wake button together.

Ficken 2 In 1 Lightning Adapter And Charger Iphone 7 7 Plus Adapter Lightning Connecter To 3 5mm Headphone Jack Cable Not Support Ios 10 3 No
Iphone headphone adapter not supported. If you see an alert learn what to do. There are several reasons why you might see this alert or similar alerts on your iphone ipad or ipod touch. You can use a pushpin to carefully insert it into your iphone or ipad charging port. Make sure that you are using the right adapter with the standard amount of power for your device. For that first of all you are required to connect your device to the charger and power adapter to the source. Then check the power supply also if you are using the usb port on your computer it may not be supplying adequate power to charge your iphone or ipad.
Heres when these alerts might appear. If the cable is providing too little or too much voltage ios may be trying to preserve the phone from damage by blocking the device through your software. Fix this accessory may not be supported problem on iphoneipad. Clean your apple accessory. But today i am getting the dreaded this accessory may message. I switched back to the still working original apple cable and it too reported that it might not be supported message.
If you see an accessory may not be supported alert. Your accessory is defective damaged or not apple certified. I found that the iphone connection seems to be sensitive to what usb port on my computer it is using. Check your headphone cable connector remote and earbuds for damage like wear or breakage. Check for debris in the headphone port on your iphone ipad or ipod touch. Then when the error message appears just dismiss it and turn the airplane mode on.
If the message this accessory is not supported by this iphone or ipadipod happens when connecting to a bluetooth accessory like speakers or headphones try forgetting the device and then adding it back while renaming that device something different than before if possible. The accessory isnt supported by your device. Your ios device has a dirty or damaged connector. Try the other original accessory charging cable or charger for your iphone ipad. Not every cable is created equally since different cables can support different voltages and this may be a major cause of your issue on your iphone or ipad. To remove debris gently brush all openings with a small soft bristled brush thats clean and dry.
Your adapter may not be providing enough power. Look for debris on the meshes in each earbud.