whois https://thegoldrushexchange.com/wp-sitemap-posts-post-1.xml

Domain:
Turn off cache
Try for webbased whois (don't expect it to work yet)
https://thegoldrushexchange.com/wp-sitemap-posts-post-1.xml
checking....https://thegoldrushexchange.com/wp-sitemap-posts-post-1.xml
   $ whois https://thegoldrushexchange.com/wp-sitemap-posts-post-1.xml
No whois server is known for this kind of object.