Your MX Records need to replace the words "yourdomain" with the domain you are forwarding your email. The priority level doesn't really matter, it can be 10, or 100, and you also can have one MX but make sure its the "s7a1".

10 yourdomain.com.s7a1.psmtp.com.
20 yourdomain.com.s7a2.psmtp.com.
30 yourdomain.com.s7b1.psmtp.com.
40 yourdomain.com.s7b2.psmtp.com.

Any Questions please email support@ironcovesolutions.com