s2._domainkey.syncedtool.com has no AAAA records.
Question and response
Question
dig s2.domainkey.u250297.wl048.sendgrid.net. AAAA
Answer
The response has no answer records.
Authority
wl048.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2397891337 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0