vercel-dns.com has no MX records.
Question and response
Question
dig vercel-dns.com. MX
Answer
The response has no answer records.
Authority
vercel-dns.com. 3600 SOA dns1.p07.nsone.net. hostmaster.nsone.net. 1657560354 43200 7200 1209600 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0