rx7713.rapidns.com has no MX records.
Question and response
Question
dig rx7713.rapidns.com. MX
Answer
The response has no answer records.
Authority
rapidns.com. 86400 SOA ns1.rapidns.com. hostmaster.rapidns.com. 2026021000 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0