Hi there,
i see the same thing here, but Internet Explorer generally works - at least with the default OSM map layer.
Looking at your site with Developer Tools enabled (F12 in IE/Firefox/Chrome),
Internet Explorer complains about some misformatted HTML in the photo that follows the map and some text. Maybe that is the cause?
Can you try to remove the photo from the article and check if it works then?
(If i look at this map on this site here with IE, it works fine...:
Demo track with OSM base layer
cheers, Frank