mail.guidagiappone.com has no NS records.
NS records for this zone are defined at guidagiappone.com.
NS records for this zone are defined at guidagiappone.com.
Question and response
Question
dig mail.guidagiappone.com. NS
Answer
The response has no answer records.
Authority
guidagiappone.com. 7200 SOA ns1.your-server.de. postmaster.your-server.de. 2026012200 86400 10800 3600000 7200
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0