mta1.epriority.com has no CNAME records.
Question and response
Question
dig mta1.epriority.com. NS
Answer
The response has no answer records.
Authority
epriority.com. 1800 SOA inetdns1.ssnc.cloud. dns.cloudflare.com. 2397576068 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0