How to redirect an iframe URL in support center
If your address for the support center is www.myaccount.com/helpcenter then all the rest of the address is being populated into the iframe's URL.
This means that www.myaccount.com/helpcenter/label would become help.myaccount.com/label.
To setup redirection, do the following:
The URL in the URL From field will return a 301 (redirect) as HTTP response when the page is visited.