bd77f1f.bf07x.hubspotemail.net has no MX records.
Question and response
Question
dig bd77f1f.bf07x.hubspotemail.net. MX
Answer
The response has no answer records.
Authority
hubspotemail.net. 1800 SOA jerry.ns.cloudflare.com. dns.cloudflare.com. 2398306228 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0