Not visible OSM layer on some machines

[AnatoliiTerentiev]

Dear Gurus!

In silverlight project  I use OSM layer and my GIS service as follows

<esri:Map x:Name="myMap" Background="White" WrapAround="true" 
          Extent="3200000,8500000,4250000,10130000" MouseClick="Map_MouseClick" >
         <esri:OpenStreetMapLayer ID="OSMLayer" Style="Mapnik" />
         <esri:ArcGISDynamicMapServiceLayer ID="My layer" 
                            Url="http://Computer:6080/ArcGIS/rest/services/karelia/MapServer" />
</esri:Map>

The site is running on IIS server. And from some computers from internet or  intranet all works fine, but on some ones OSM layer not visible, when layer of my gis service - is visible. What may be the reason?

[AnatoliiTerentiev · Accepted solution]

I solved the problem by adding external dns address.

"Some" computers were in intranet and uses only internal dns server.