IFTTT with dns url not working

I am trying to get IFTTT to work with a dynamic dns url.

I have setup ddclient on my pi and when I ping the url I get the correct IP address.

I know the url works because I am able to access the HA interface through it.

However when trying to access the api through IFTTT it does not work.

It will say it has been run, but it wont actually do anything.

Changing the url to my external ip address works.

URL:
http://Redacted.us:8123/api/services/script/power?api_password=Redacted

Method:
Post

Content Type:
application/json

Body: blank