I'm using GetResponse as my email platform, and I needed to configure my DNS settings so the landing page is connected to my website (and therefore the URL is consistent with my brand.)

I spent A LOT of time trying to figure it out on my own, and so I just thought I'll put it out there for other people to see - YOU CAN'T CONFIGURE THE CNAME YOURSELF.

That's the answer :)

You will have to contact WA site support and they will do it for you :)