My FR935 was replaced, I added it to my account, and every time it syncs an activity the watch displays "sync failed" but on the same screen "your activity is ready to view" is displayed. Steps and sleep data syncs without errors. The sync log says "invalid file size or name" when the sync contains a course. I'm travelling and have no access to a PC. Tried power off/on of watch and phone, logging out and in of the mobile app.
myGarmin has an incorrect device list, I have 3 devices paired to the phone, only the newly replaced FR935 shows up in myGarmin. Not eager to try creating a new account. Maybe someone recognizes this and has advice?
Update: Created a new account, reinstalled GCM, added the new FR935, no difference. Syncing ends very quickly. No courses, new or old, are transferred. Error message in device sync audit remains the same. Can't say if syncing of activity data is working OK, I revoked the consent for that (don't need uploads at this time).