Initializing the headset to restore factory settings
Disconnect the micro-USB cable, turn off the headset, then press and hold the button and the - button simultaneously for more than 7 seconds.
The indicator (blue) flashes 4 times ( ), and the settings such as the volume adjustment are reset to the factory settings. This operation resets volume settings, etc., and deletes all pairing information. In this case, delete the pairing information of the headset from the Bluetooth device, and then pair them again.
If the headset does not operate correctly even after initializing, consult your nearest Sony dealer.