Try doing a reset:
· Power ON the device, then press and hold the "Volume+" and the "Play/Pause" buttons at the same time. When the device switches off after a few seconds, sounding the OFF prompt, it has been reset.
· After performing the master reset in your speaker, please delete/unpair the JBL Charge 3 bluetooth history in your device (phone/laptop/tablet) and re-connect.
This reset is also a great way to get rid of any annoying (interfering) connected devices after too many of your buddies have used your speaker to play their music.