Diagnosis
A solid red LED on the subwoofer indicates it is powered but not paired. The wireless link between the soundbar and subwoofer has failed to establish or has been lost.
How to Fix It
Initiate manual pairing. Unplug both the soundbar and subwoofer from power for 30 seconds. Plug in the soundbar first and wait for its display to settle. Then plug in the subwoofer. Immediately press and hold the 'PAIRING' button on the back of the subwoofer for 5 seconds. Its LED will blink rapidly. The soundbar will search for 90 seconds. A connected state is confirmed by a solid blue LED on the subwoofer.
If That Didn't Work
Proximity or signal interference is likely. Move the subwoofer to within 3 feet of the soundbar, facing its front. Remove any large metal objects or wireless devices between them. Repeat the pairing process. Do not place the subwoofer inside an enclosed cabinet.
Heads Up
The subwoofer uses a specific 5.8GHz wireless band. A nearby wireless router, microwave, or cordless phone can block the signal. Temporarily disable other 5GHz devices during initial pairing.