Make sure Bluetooth is turned on. You should see the little Bluetooth symbol at the top of your phone’s screen. If you don’t, go into the settings to enable it.
Turn on discoverable mode. First, go into your phone’s settings and turn on Bluetooth.
Make sure the two devices are in close enough proximity to one another. it’s probably worth noting that you should make sure any devices you're trying to pair are within five feet of one other.
Power the devices off and back on. A soft reset sometimes can resolve an issue. With phones, an easy way to do this is by going into and out of airplane mode.
Power down likely interferers. Say that faithful Bluetooth speaker usually connects to your partner's smartphone instead of yours. If you're having trouble pairing your phone with the speaker, it could be because the speaker (or headphone) is trying to activate its usual connection. Some older devices are very simple. They just try to connect with the last thing they paired with. If a Bluetooth device was previously paired with something else, turn off that other gadget.
Charge up both devices you're trying to pair. Some devices have smart power management that may turn off Bluetooth if the battery level is too low. If your phone isn't pairing, make sure it and the device you're trying to pair with have enough juice.
Delete a device from a phone and rediscover it. If your phone sees a device but isn’t receiving data from it, sometimes it helps to start from scratch. In iOS settings, you can remove a device by tapping on its name and then Forget this Device. In Android settings, tap on a device’s name, then Unpair. After removing a device, start at step 1 on this list.
Get away from the Wi-Fi router. Another potential obstacle to successful pairing is interference from devices that use the same spectrum, such as your Wi-Fi router. “Wi-Fi has been designed to cope with this, but it might not be a good idea to have your devices directly on top of the router,”
Move away from a USB 3.0 port. Interference from USB 3.0 is also possible. Newer laptops, for example, often have the higher-speed USB 3.0 port, so if the connection isn't happening, try pairing your Bluetooth gadgets away from the computer.
Make sure the devices you want to pair are designed to connect with each other.Whether it’s a headset, speaker, mouse, keyboard, camera or something else, your device has a specific profile that spells out what it can connect with. If you’re not sure, check the user manual.