mailer.bubblesmail.net has no CNAME records.
Question and response
Question
dig mailer.bubblesmail.net. NS
Answer
The response has no answer records.
Authority
bubblesmail.net. 573 SOA ns49.domaincontrol.com. dns.jomax.net. 2023091900 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0