Google News sitemap not visible

I have enabled the Google News sitemap in WordPress >> Reading. However the news sitemap does not show any entries.
http://luxurylaunches.com/sitemap-news.xml

On the other hand the normal sitemap works fine – http://luxurylaunches.com/sitemap.xml

I tried creating a blank sitemap-news.xml as well but it would not help.

What could be wrong?