ns4.perimetercenter.com has no MX records.
Question and response
Question
dig ns4.perimetercenter.com. MX
Answer
The response has no answer records.
Authority
perimetercenter.com. 300 SOA ns1.ral.hostedsolutions.com. hostmaster.hostedsolutions.com. 2006080727 10800 3600 2419200 300
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0