Samsung CU8000 Crystal UHD TV will not pair with Bluetooth headphones or speakers

The checks in more detail

since most headphones connect to the last device, and that they are close to the TV, with a clear line to the TV's Bluetooth radio, which is at the back. Restart the headphones and search again. If an old pairing is stale, remove it from the list and pair again. Once paired, the TV sends its sound to the headphones, and the speakers go quiet. If you hear nothing, check that Sound Output is set to the Bluetooth device and that the TV's volume and the headphone volume are up.

If the sound is delayed against the picture, which is common with Bluetooth, look in the sound settings for an Audio Delay option or a lip sync setting, and use a headset that supports a low-delay codec. A TV that drops the connection may be affected by Wi-Fi traffic, so move the headphones closer and the router's 2.4 GHz band away from the TV. Samsung TVs generally connect to one Bluetooth audio device at a time, and some versions allow Multi-Output Audio to play on the TV and a Bluetooth speaker together, found in the Sound Output menu.

Keep the TV updated in Settings, Support, Software Update, since Bluetooth fixes arrive that way. If the TV will not connect to any device, restart it by unplugging for a minute and, as a last step, reset sound settings in Settings, Support, Self Diagnosis, Reset. A soundbar that connects through HDMI eARC is more reliable than Bluetooth for regular use. If the TV's Bluetooth radio seems dead, contact Samsung with the model number.