mail.adderglobal.com has no CNAME records.
Question and response
Question
dig mail.adderglobal.com. NS
Answer
The response has no answer records.
Authority
adderglobal.com. 5561 SOA ns1.adderglobal.com. admin.adderglobal.com. 2025110303 28800 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0