a rear speaker sometimes not conecting to my LG S95QR soundbar

Hi, I have an LG S95QR sound bar and for a few days one of the rear speakers has not connected when I turn it on, I have to turn the bar off and turn it on again and then it connects. I have tried doing a hard reset of the bar and it keeps happening, not every day but from time to time. Is there a way to reset a single speaker or a way to solve this problem which is quite annoying, thank you