spf2.vivo.com.br has no NS records.
NS records for this zone are defined at vivo.com.br.
NS records for this zone are defined at vivo.com.br.
Question and response
Question
dig spf2.vivo.com.br. NS
Answer
The response has no answer records.
Authority
vivo.com.br. 900 SOA aquarius.vivo.com.br. root.vivo.com.br. 2014084585 10200 3600 604800 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0