mail.aumanaged.com has no CNAME records.
Question and response
Question
dig mail.aumanaged.com. NS
Answer
The response has no answer records.
Authority
aumanaged.com. 22 SOA nssyd01.aumanaged.com. alerts.crucialparadigm.com. 2026022600 4800 300 1209600 100
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0