Lately I have trouble syncing my 645M with Garmin Connect on my Mac. I have tried all the usual - restart watch and phone, uninstall Connect and reinstall. I have the setting on my iPhone to always allow location. This helps for a time or two and then the problem reappears. The green dot (see top of screenshot) is on meaning the watch is connected to my phone. If I press the blue sync button, it spins a few times and then stops.
I can still sync by pressing the top left button on my watch and then choosing sync. However, that is a pain and only works when I have wifi connection.
Any suggestions?