s2._domainkey.syncedtool.com has no NS records.
NS records for this zone are defined at syncedtool.com.
NS records for this zone are defined at syncedtool.com.
Question and response
Question
dig s2.domainkey.u250297.wl048.sendgrid.net. NS
Answer
The response has no answer records.
Authority
wl048.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2397986692 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0