Try forgetting your AirPods from your device. Then reset the AirPods as shown below. Once the resetting is completed then pair them again with your iPhone. If this does not solve the issue then please contact ➔ Apple Support
Reset your AirPods
You might need to reset your AirPods if you can't connect to them, if they won't charge, or to fix a different issue.
Put your AirPods in their case
Close the lid. Wait 30 seconds, then open the lid.
On your iPhone, iPad, or iPod touch, go to Settings
Go to Settings > Bluetooth and tap the "i" icon next to your AirPods.2 Then tap Forget This Device, and tap again to confirm.
Reset your AirPods
With the lid open, press and hold the setup button on the back of the case for about 15 seconds, until you see the status light flashing amber.
Reconnect your AirPods
With the lid open, place your AirPods close to your device. Follow the steps on your device's screen.
Axel F.