DIAGNOSIS The soundbar's Bluetooth pairing list is full (it stores about 8 devices) or has a corrupted entry, preventing new connections.
FIX Clear the entire Bluetooth pairing list. On the soundbar remote, press and hold the Source button for more than 5 seconds until "BT INIT" appears on the display. This erases all paired devices.
IF THAT DIDN'T WORK Perform a full system reset. Unplug the soundbar, then press and hold the Play/Pause button on the soundbar itself (not the remote) while plugging it back in. Release after 5 seconds. Re-pair your phone.
HEADS UP After a reset, you will also need to re-pair the wireless subwoofer (it should auto-connect, but if not, use the ID SET button) and redo any Wi-Fi or TV connection settings.