Pairing with bluetooth headset fails (PLT BBFIT 3200)

Hi all

The Venu 3 is my 3rd generation of Garmin watch with music; so far I always managed to pair my bluetooth headset with the Garmin device - but now it fails.

The Venu 3 finds the headset by searching for headphones but the pairing process is aborted with the massage "no connection".

I did reset the watch and the headset several times, turned off bluetooth on the phone so that the Venu 3 is standalone;

also the bluetooth headset is able to connect to my smartphone,  Vivoactive 3 Music, Venu 2 Plus and other devices without any flaw.

Any idea what else I can do to get this to work?

Thanks and merry x-mas