o4.sendgrid.kubra.com has no MX records.
Question and response
Question
dig o4.sendgrid.kubra.com. MX
Answer
The response has no answer records.
Authority
kubra.com. 3600 SOA pdns112.ultradns.com. admin.kubra.com. 2023057439 3600 900 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0