smtp.sea.tierpoint.com has no MX records.
Question and response
Question
dig smtp.sea.tierpoint.com. MX
Answer
The response has no answer records.
Authority
sea.tierpoint.com. 86400 SOA ns1.ral.hostedsolutions.com. hostmaster.hostedsolutions.com. 2016060307 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0