I have some problems in my webpage to download the GOX. When I try to download the GPX open a new windows and I can’t save in my computer, therefore the user can’t download correctly the file.
I try it on your webpage and it work as it should. The only thing to know: just right-click and use ‘save as’. The .gpx file sometimes is misinterpret as a XML file and the content will display instead of saving it to a file. So I think your problem is related to browser settings on your side. To verify just try another browser.