I have a request from a third-party vendor to do a HTTP Post to Marketo. I've read through some of the past discussions, but I'm not clear on exactly what I need to provide to this vendor. I've put together a landing page/form for this project, but I'm not sure what we need to pull off of that for the vendor.
You may want to open a support ticket and specify the exact URL and all the parameters you're passing. If some of the required parameters are missing or incorrect it will give a 404. So a 404 error is not necessarily a sign that the URL is incorrect.
Add a few things--a correct submission return code we see is 200 and not 302. In addition, if passing multipe-value (from a multi-select picklist), do not pass a multiple key/value pairs, instead pass them as as a single key and the values as a semi-colon delimited list.
Things we learned the hard way
Make sure your firewall isn't blocking your posts (took a while for us to figure out in the test environment).
Firefox add-on called Poster is your testing friend
404 is always returned if there's anything wrong with the post