mail99.gvp.telefonica.com has no NS records.
NS records for this zone are defined at gvp.telefonica.com.
NS records for this zone are defined at gvp.telefonica.com.
Question and response
Question
dig mail99.gvp.telefonica.com. NS
Answer
The response has no answer records.
Authority
gvp.telefonica.com. 900 SOA ns1-201.azure-dns.com. video.ops.support.telefonica.com. 2022112901 900 600 86400 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0