dyndns.info has no MX records.
Question and response
Question
dig dyndns.info. MX
Answer
The response has no answer records.
Authority
dyndns.info. 1800 SOA ns1.dyndns.org. hostmaster.dyndns.org. 2829343767 10800 1800 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0