spf6a.orange.com has no NS records.
NS records for this zone are defined at orange.com.
NS records for this zone are defined at orange.com.
Question and response
Question
dig spf6a.orange.com. NS
Answer
The response has no answer records.
Authority
orange.com. 3600 SOA dns1.comlaude-dns.com. dnstech.comlaude.com. 1755272043 86400 7200 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0