u45748045.wl046.sendgrid.net has no NS records.
NS records for this zone are defined at wl046.sendgrid.net.
NS records for this zone are defined at wl046.sendgrid.net.
Question and response
Question
dig u45748045.wl046.sendgrid.net. NS
Answer
The response has no answer records.
Authority
wl046.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2399676017 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0