mx6.printhosting.com has no MX records.
Question and response
Question
dig mx6.printhosting.com. MX
Answer
The response has no answer records.
Authority
printhosting.com. 1800 SOA ihsaddc01.printhosting.com. dom-admin.efi.com. 5933227 900 600 172800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0