I have a Garmin 820 and a Samsung S6. Connect app is loaded and works for everything but starting a grouptrack. I have followed the manual to a tee for setup and Garmin techs have given me the same instructions. I have reloaded the Garmin Connect app thinking it may have been a glitch in the app but no luck. I have all the latest versions of software, firmware and underwear. My wife has the exact same setup as I do and hers works fine so I know it is possible and I know I have done everything right on my 820 and my phone. Anyone else out there with this issue???
