s2._domainkey.xlhost.com has no NS records.
NS records for this zone are defined at xlhost.com.
NS records for this zone are defined at xlhost.com.
Question and response
Question
dig s2.domainkey.u35279547.wl048.sendgrid.net. NS
Answer
The response has no answer records.
Authority
wl048.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2399457030 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0