www.noip.com has no MX records.
Question and response
Question
dig www.noip.com. MX
Answer
The response has no answer records.
Authority
noip.com. 1800 SOA ns2.no-ip.com. hostmaster.no-ip.com. 2023082181 10800 1800 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0