GPX visible in conversion tool and in MyTracks Detail but not onto map

I’m a complete newby on OpenStreetMap.

I have to print a map in which is highligheted a marathon through woods. I have KMZ files created in GoogleEarth by a user and I converted it in GPS using suggested url (

I succesfully uploaded this GPX and I’m able to see its details in my traces area but, clickin on “map” link it does not show anything.

If I try from conversion tool (this page to display converted GPX into GoogleMaps for example, visualization is perfect.

So, why is not visible in OpenStreetMap?