S8+ annoying sound when Bluetooth smart watch out of range

[Android Central Question]

I have a smart watch connected to my phone. Every time I leave my phone and I am out of range of the watch my phone makes a loud noise like an app notification - even when the phone is on mute!

The watch is a cheap one it has an app but not many settings.

Please can someone advise how I stop this it is driving my colleaguesin my office insane every time I leave the room!