mail.cobranet.ro has no CNAME records.
Question and response
Question
dig mail.cobranet.ro. NS
Answer
The response has no answer records.
Authority
cobranet.ro. 300 SOA ns2.cobranet.ro. hostmaster.cobranet.ro. 2017071316 16384 2048 1209600 2560
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0