Syncing problem

I have a Garmin Edge 810 and I used the Garmin Connect Mobile app on my Lumia 730 (Windows 10 Mobile) to upload my rides via Bluetooth without any issues for many months. I don't carry my phone with me on my rides, but when I would arrive home, I would simply open the GCM app, hit the sync button and my ride (.fit file) would be uploaded to my Garmin (and Strava) accounts without a hitch.
Three days ago, I reset my Garmin and since then I haven't been able to sync via Bluetooth at all any longer. I know that there were some issues with the Garmin servers last weekend, but as far as I know, that's over now. However, what happens is the following: my Edge 810 and my mobile phone are connected alright, the Edge shows in the GCM app and when I hit "Sync", it syncs (blue, then green stripe at the bottom), but even though it says "sync complete", the activity is NOT uploaded to my Garmin (and Strava) accounts and is not shown there at all. The activity is there on the Edge though, and I can also sync it via USB and Garmin Express on my laptop (if I sync it there, it shows up as an activity in my Garmin Connect, unlike via Bluetooth).
I have reset the Edge 810 several times (both Factory and the so-called Super Master Reset including formatting, it still runs the up-to-date 6.30 firmware) and have tried unpairing the phone and uninstalling/reinstalling GCM on the phone. I'm at my wit's end, because nothing has worked, I still get the same error, except that according to GCM it's not an error (i.e. it shows "sync completed", but it doesn't actually sync the data). Could anyone help?
  • Been happening to me for about a month. Sync use to happen almost instantaneously after I clicked save and done on watch. Last 4-5 weeks sporadic at best and recently not at all. So frustrated with Garmin. The recent update to 4.15.1 did nothing to help.
  • I chatted with a very helpful and patient tech support guy from Garmin yesterday for several hours. He guided me through a new formatting of the Garmin (I'd already done that myself before), then he had me un-pair and re-pair the Garmin to the phone but in the end it didn't help. I still have the same issue: the screen shows syncing (though it's too fast: the blue status line at the bottom of the app screen changes to the green "sync complete" almost immediately), but the activity does not actually upload to GCM (and GC). I've tried to force the upload from the Garmin (Folder icon>select Ride>Upload, and after 30-40 seconds it just gives me the "Upload failed" message (interestingly, however, when I do this, the app shows the same (too fast) syncing (blue to green at the bottom) and gives the sync completed message. The Garmin support guy could not really think of anything, except that since support for Windows Mobile has ended, my syncing was only successful as long as the app legacy worked and the Garmin was paired to the app, but once I reset the Garmin and re-paired them, the app functionality (or the BT connection between the two devices) was broken and will not likely be restored.
    What I find very strange is the following:
    1. I only upgraded to Windows Mobile 10 (from 8.1) in November 2018, in order to be able to use GCM's BT syncing (GCM is not available under WM8.1), but I had no problems until last Sunday in those 3-4 months AND as far as I know, the GCM app is the same (i.e. I have not had any updates to the app installed on the phone). The Garmin firmware has not changed either. So why was the GCM in the Windows store still perfectly functional in November 2018 (one year after Garmin discontinued support for Windows Mobile), but suddenly stopped working in mid-February 2019???
    2. While Windows seems to be blamed, I have found several identical issues to mine on this very forum from 2-3 years ago with other Garmins and both iOS and Android phones. In those cases, it seems that Garmin took care of the matter with patches/updates. I understand that they won't waste any time on the Windows version of their app, but it is still unacceptable to lose functionality all of a sudden.
    And I find it deeply suspect that the issue started right after the alleged Garmin server outage last weekend (mid-February), which affected lots of users worldwide.
  • Update: tested with an Android phone, everything works flawlessly. Time to say goodbye to my Windows phone :(