mx1.retemetis.net has no MX records.
Question and response
Question
dig mx1.retemetis.net. MX
Answer
The response has no answer records.
Authority
retemetis.net. 86400 SOA dns1.retemetis.net. donato.conte.metissrl.it. 2025040700 10800 3600 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0