Problem with Sitemap

Prolem with sitemap Have a look into this when I give https://telecomtalk.info/sitemap.xml the sitemap is show properly same in the case when I access using https://www.telecomtalk.info/sitemap.xml a messed up page of sitemap is shown why is that happening when I give www ?

And same in the case when I search google with keyword as

Site:telecomtalk.info my entire site is show https://www.google.co.in/search?q=site%3Atelecomtalk.info

But same when I use keyword as site:www.telecomtalk.info https://www.google.co.in/search?hl=en&q=site%3Awww.telecomtalk.info

I get an error as “Your search site:www.telecomtalk.info –did not match any documents.”

Why is this happening why when I add “WWW” and search stuff I get error is this the problem with the host or my domain what should I do to sort this problem out.