mail1.prioritycolo.com has no CNAME records.
Question and response
Question
dig mail1.prioritycolo.com. NS
Answer
The response has no answer records.
Authority
prioritycolo.com. 3274 SOA ns1.prioritycolo.com. admin.prioritycolo.com. 2026020601 1800 900 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0