Leaflet custom tile server not showing osm .pngs

Hello All, I am working in a Windows environment. In an .aspx web form

L.tileLayer('http://tile.osm.org/{z}/{x}/{y}.png', { }).addTo(map);

will show the correct OSM tile.

I also have some custom tiles on MyOwnCustomServer.

If I type http://MyOwnCustomServer/7/19/43.png into my web browser, it will show the correct tile.

However,

L.tileLayer('http://MyOwnCustomServer/7/19/43.png', { }).addTo(map);

AND

L.tileLayer('http://MyOwnCustomServer/{z}/{x}/{y}.png', { }).addTo(map);

do not show any OSM tiles.

Does anyone know what I need to do to get this to work? Thanks in advance.