When I use the manual upload button in Garmin Connect I get the following error message.
An error occurred with your upload. Please try again.
I don't think I have ever been able to successfully upload a GPX file to Garmin Connect but can't be 100% sure, but I am sure I'm not doing something wrong, it should be fairly simple steps... click upload > manual upload > select your gpx file > then click upload activities from file - the Garmin Connect dialog says "We currently support .tcx .gpx and .fit files."
I've gone around in circles in the forums and online looking for information but not found anything that resolved the problem for me. Onc suggestion was to modify the GPX file header but not sure exactly what changes would help.
Does Garmin acknowledge if there is a problem with the manual upload feature?