Unfortunately, we can’t directly offer to open a file when clicking on it, because a website can’t do that. You would have to open the website and then click on import to select the file.
I have to switch to english as I have no accurate translation in dutch. You have to modify the Standard App in Windows for file type *.gpx. Go to the search function in Windows and look for ‘standard app’ - there you must remove ‘Adobe illustrator’ as standard app for gpx files