DNS address could not be found

hello sir

I am using infinityfree server with external domain name. I have hosted 3 website in 3 following sub domain.

product-feed.templatemaza.com
compare-similar.templatemaza.com
price-comparison-india.templatemaza.com

All above website is working good. but suddenly getting error “DNS address could not be found” in one of the above website price-comparison-india.templatemaza.com today.

I have check nameserver and it is correct and also other two website is working good.

I had created sub domain in infinityfree cpanel and website was working for past 4 month. but problem is happened now today. please suggests me.

From the looks of it, the DNS records for your domain name were removed from the nameservers. I’ve not seen that happen before. Can you try to remove the domain name from your account and then add them again? That should fix any bad settings.