fēnix 5x + AllTrails .gpx course fails to import both through iOS Connect & Garmin Connect web portal

Hi

iPhone 13 Pro Max, all attempts to load .gpx either by importing from Dropbox/GDrive in iOS into Connect app OR on desktop through Connect web portal via USB-connected Fenix are resulting in failure.

On iOS I receive error message "Oops! Something went wrong loading your courses." while on desktop (through Chrome) I get an instant error "An error occurred with your upload. Please try again."  Both processes worked like a charm on my previous iPhone XS Max. I am on iOS 15.2.

Can anyone please help shine any light on this?

Thanks!