mail.bits.net.do has no CNAME records.
Question and response
Question
dig mail.bits.net.do. NS
Answer
The response has no answer records.
Authority
bits.net.do. 148 SOA ns1.bluehost.com. root.box5223.bluehost.com. 2021071500 86400 7200 3600000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0