If one of your earbuds stopped working, resetting your AirPods might do the trick. To do this, put your AirPods in their case and open the lid, then go to your device's Bluetooth settings and forget your AirPods. Next, press and hold the setup button on the back of the case until the status light flashes amber, then release. The light should flash white, indicating your AirPods are reset. Try reconnecting them to your device and see if that solves the issue with the non-working earbud. This usually fixes connectivity problems, so it's worth a shot.