mail.server.aderlo.cloud has no CNAME records.
Question and response
Question
dig mail.server.aderlo.cloud. NS
Answer
The response has no answer records.
Authority
server.aderlo.cloud. 1996 SOA ns1.aderlo.cloud. hostmaster.server.aderlo.cloud. 2025100200 2000 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0