What are you trying to do exactly? I that the name does resolve to an IP address so that part is working fine.
If you're trying to port forward something, make sure that any devices that are in front of the MX (e.g. ISP router) are also setup correctly to forward traffic to the MX, either through single port forwarding or by setting up the MX as DmZ device.
Also, some providers keep certain ports closed.
It's best not to post your actual Dynamic DNS name in a public forum.