mail.bear-vault.com has no CNAME records.
Question and response
Question
dig mail.bear-vault.com. NS
Answer
The response has no answer records.
Authority
bear-vault.com. 300 SOA root-dns.netcup.net. dnsadmin.netcup.net. 2026022090 28800 7200 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0