[PROBLEM] why can headphones not be found with bluetooth scan

[trailie]

Hello, I have installed moode unto a Pi4 and have it playing into my valve amplifier just fine.  However when I try to scan for devices with bluetooth it won't discover my Sony headphones (WH-1000mk3). I know that moode bluetooth is working because I can find my phone, pair it up and then play audio from my phone into moode and out to the amplifier. 

Why do you think moode won't discover the headphones when I scan for devices ?  They work and pair ok with my laptop and phone.

Ralph.