mail.gorillaservers.com has no CNAME records.
Question and response
Question
dig mail.gorillaservers.com. NS
Answer
The response has no answer records.
Authority
gorillaservers.com. 294 SOA ns1.gorillaservers.com. hostmaster.gorillaservers.com. 2025031101 1800 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0