BT headphone paired but no audio

I have a S912 box running 9.2.2. I just got a new pair of BT headphones to replace an older (>3yrs) BT headphone. I can’t get this new headphone to work. It pairs successfully but there is no audio output after I set the audio to output Bluetooth. The old pair works fine. Is it because the new one is running on newer BT protocols that’s incompatible with my box?

Could anybody point me to ways I can debug this problem? Thanks!