u2437426.wl177.sendgrid.net has no NS records.
NS records for this zone are defined at wl177.sendgrid.net.
NS records for this zone are defined at wl177.sendgrid.net.
Question and response
Question
dig u2437426.wl177.sendgrid.net. NS
Answer
The response has no answer records.
Authority
wl177.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2399450592 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0