NameCheap Dynamic DNS Failed or Notconnect

Trying to get NameCheap Dynamic DNS to work, but I'm either getting a "Failed" error when I configure it and use the below. I've tried "" as the hostname as well which gives a "notconnect" error instead. Any idea what I've got misconfigured? I've activated it and pasted the code from the dashboard.

Added TAG
[edited by: emmosophos at 10:34 PM (GMT -7) on 14 Apr 2021]