dns3.supremedns.com has no MX records.
Question and response
Question
dig dns3.supremedns.com. MX
Answer
The response has no answer records.
Authority
supremedns.com. 2560 SOA ns1.supremedns.com. hostmaster.supremedns.com. 1772416206 16384 2048 1048576 2560
Additional
The response has no additional records.