Only the www version works to me, so it seems like the DNS records for your domain were corrupted. Can you please remove and re-add the domain from the “Addon Domains” section of the Control Panel? That should fix them.
“Bad NS list” is not a particularly specific error message. Could you try to remove the epizy.com nameservers from that list and only keep the byet.org nameservers? The ns1 and ns2 servers point to the same IP address, and I can imagine some systems dislike IP reuse.