Why would www.domain stop working?

After a graceful reboot using WHM, all but one of my domains get DNS errors when attempting to reach the domains using www . domain . com They are still reachable using domain . com. One domain is still reachable using the www

The DNS zones all look fine and untouched. I just don't get it and can't figure out how to repair it.

Any help will be very much appreciated. Thank you.

 

 

 

 

Top