mail2.hostsailor.com has no CNAME records.
Question and response
Question
dig mail2.hostsailor.com. NS
Answer
The response has no answer records.
Authority
hostsailor.com. 1800 SOA chuck.ns.cloudflare.com. dns.cloudflare.com. 2397154445 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0