Can I use a no-ip URL in the VNC client?

[TW]

I am unable to access my VNC server by entering its URL in a VNC client.
I'm wondering if this is supposed to be possible.

Background:

I registered with no-ip.com so my dynamic WAN IP address has a consistent
URL.

I can successfully ping this URL.

I can access my VNC server over the internet by entering the WAN IP address
of my VNC server.

But if I enter the URL, VNC will respond after a few seconds with "Failed to
connect to server".

Any suggestions?

Thank you.