Try this solution
Follow the guide for reconnecting to a Garmin watch
If your Melomania earbuds do not automatically connect to your Garmin Watch when removing them from the charging case:
1
Hold the touchscreen on your Garmin.
2
Select Settings.
3
Select Sensors & Accessories.
4
Select Melomania L or R.
5
Select Connect.
You will be able to play & pause your music using the Melomania button controls. We are, however, aware that it may not be possible to control volume using the control on the earphones and therefore must be adjusted using the watch. We apologise for any inconvenience this may cause.