Hi,

I’ve been using this great plugin for about a year and lately one user of my website noticed that you were not able to dwonaload GPX files with Chrome (still working fine with Firefox.
It seems to be related to cross-site download (see https://stackoverflow.com/questions/49474775/chrome-65-blocks-cross-origin-a-download-client-side-workaround-to-force-down).
Even if the GPX files are on the same site, as wp-gpx-map use a full URL instead of a relative path, chrome consider it as external.
I’v fixed it by removing:

// wpml fix
$dummy = ( defined('WP_SITEURL') ) ? WP_SITEURL : get_bloginfo('url');
$gpxurl = $dummy.$gpxurl;

in wp-gpx-maps.php.