Trying to implement my first Forms 2.0 on a page outside of Marketo.. however when I add the form embed code to my landing page (just flat HTML right now) - I get the following error.
Error loading form: Object {error: true, errorCode: 400, message: "Subscriber '751-HBN-596' is not valid"}
Any clue on what going on here? My Marketo instance is certainly valid and alive!