Many new Bluetooth devices (e.g. wireless headphones) automatically go into pairing mode the first time you turn them ON. Your device becomes discoverable on its own. At this point, your device doesn’t have any pairing information saved. However, when you pair a second device, you must manually activate pairing mode. Your device won’t enter pairing mode automatically, unlike the first time.

NOTE: For how to enter the pairing mode onyour Bluetooth device, refer to the manual supplied with the product. Some TVs support Bluetooth remotes, but not Bluetooth headphones. The headphones need a different Bluetooth profile than the remote control. Tap on the gear icon next to the device you wish to Disconnect or Remove (forget its pairing information). Bluetooth pairing is similar. When two Bluetooth devices are pairing, they exchange information. They establish a connection and recognise each other in the future without any introduction - unless one device forgets the other one or vice versa. Bluetooth pairing will occur, or the Bluetooth connection will be activated if you’ve previously paired the devices.After the computer has loaded the device and the drivers for the headphones, you should see that the device has been connected successfully. With many Sony Bluetooth devices, activating pairing mode is done by pressing and holding the pairing/power button on your device for about 7 seconds. You will often hear an audio cue or see a blue flashing LED to inform you that your device has entered pairing mode. Your device will remain in pairing mode for a few minutes and will turn itself off if the pairing procedure isn't successful.

Although uncommon, it’s possible that two devices are successfully paired, but refuse to connect. If you’re sure this is not caused by a low battery level or a mismatch of Bluetooth profiles, delete the pairing information and pair the devices again to solve this glitch. You can delete ( Forget / Remove device) Bluetooth pairing information in your phone’s or computer’s Bluetooth menu. If your Xperia is currently connected to a Bluetooth device, the connected device will appear under ' Available Media Devices', as shown in the screenshot below.For more information, visit the article: What’s the easiest way to pair my Bluetooth headphones with an Android phone?