I offer a GPX file for download. Here is the code (http://auto-pedestres.lu/index.php/auto-pedestres-no-regiounen/ap-regioun-guttland/79-bonnevoie):
<a class="agbutton3_61122a7b2142c" href="http://auto-pedestres.lu/images/com_aggpxtrack/AP_Bonnevoie.gpx" download="">Download als GPX Datei</a>
Now website visitors keep reporting that they can't open the GPX file on the smartphone. On the computer it works.
I myself can open the file without any problems.
Therefore, I thought at first that it is due to the smartphone settings. Because I became skeptical, I have now asked someone who has the problem to test another website (https://draussenlust.de/radfahren/2020/fahrradtour-luneburger-heide-undeloh-handeloh/#map) . Here the link is included almost exactly as with me:
<a href="https://draussenlust.de/wp-content/uploads/gpx/0820_Fahrradtour-Lueneburger-Heide-Undeloh_Draussenlust-de.gpx" target="_new" style="font-size:16px;" title="Download der Tour als GPX-Datei: /wp-content/uploads/gpx/0820_Fahrradtour-Lueneburger-Heide-Undeloh_Draussenlust-de.gpx" download="">⇩ Download als GPX-Datei »</a>
On this other website, the visitor can download the GPS file and open it with the app of his choice.
Which settings could be different in my case?