mail.wahju.com has no CNAME records.
Question and response
Question
dig mail.wahju.com. NS
Answer
The response has no answer records.
Authority
wahju.com. 3405 SOA ns100.wahju.com. hostmaster.wahju.com. 2020051914 14400 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0