mx.nubeo.network has no CNAME records.
Question and response
Question
dig mx.nubeo.network. NS
Answer
The response has no answer records.
Authority
nubeo.network. 3385 SOA diana.designplus.cz. domeny.designplus.cz. 2023120871 3600 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0