Hi Someshvar,
The URL you provide won't work. The reason being that it contains a HTML fragment (everything after the #), which has to be evaluated by the client. The Maps component is expecting that when it retrieves content from a URL that it will be a valid GeoJSON. Accessing that URL will result in an HTML page with JavaScript that eventually results in it doing the right thing. If the site you are using can provide a permalink (a form of link where the contents will be stable) for the GeoJSON, then it should work with the maps component. Otherwise, your best bet is to download the file as a geojson file and then upload it into App Inventor.
My guess is that the internal error is due to the fact that we are expecting GeoJSON and you upload a saved copy of the HTML page, which then fails in an interesting way.
Regards,
Evan