wl179.sendgrid.net has no TXT records.
Question and response
Question
dig wl179.sendgrid.net. TXT
Answer
The response has no answer records.
Authority
wl179.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2398406529 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0