Thank you for your reply. Unfortunately if I tap on that device an alert tells me that the device isn't connected and that I should connect it in order to do anything... As said I don't own that watch anymore :confused:
One of these might work. I don't have an unavailable Bluetooth Garmin, so can't test this. Might be different, depending on your model of phone.
Remove old device from Bluetooth: If the old device is listed in Paired BT devices, then unpair. Open GCM.
Delete app cache: Settings >> Apps >> Connect >> Force Stop >> Storage >> Clear cache. Open GCM.
Delete app data: Settings >> Apps >> Connect >> Force Stop >> Storage >> Clear data. Open GCM. This will set GCM to "first run" condition, so you would need to sign in and setup your current device. In settings on your device set to "pair mobile device."