I can't synch with my Garmin Fenix

I'm on my trial period and trying to figure out how to get the most from Noom. I use my Garmin watch for steps and all activities. Although Garmin is listed in compatible devices, it does not connect,(error 404). I can use my Apple health to log steps manually but I don't even use Apple health. Has anyone been able to connect with Garmin. I like the app but if it's not compatible, then why get a subscription. Any help would be appreciated. Also, Noom answers through AI.