Check the manual on how to re-pair but also move the sub to within a foot of the bar when pairing.
If that doesn't work, check your warranty and arrange for repair.
My LG subwoofer is flashing green light, i have tried the solutions from the manual to Vol Min and hold mute for three seconds however WL Reset does not come up on the soundbar. I have also unplugged in and out and moved to a different location.
Anybody have any Recommendations?