I have just received the Galaxy Fit 3 which is the successor to the 4 year old Galaxy Fit 2, and in this video, I show you how to setup and connect the Galaxy Fit 3 to your Android phone.
Please make sure your phone is running android 10.0 and above. If that's the case, restart the watch. If the problem persists, turn off and turn on Bluetooth on your phone. This is probably a connectivity issue.
