using form capture

I'm trying to use form-capture (CRM-2106 online)

We have an existing form online. And I would like the visitors whom submit this form to become contacts in CRM

The html of the form is tracked by Clickdimensions; I can see the visits.

1. I've made a form capture,

2. made sure all fields are mapped to fields in CRM and given the fields same name as in the HTML of the form

3. placed the "action" URL in the HTML of the form

All is activated and I think it should work, but testing it, no contact in CRM is generated. Have I missed a step or have I misunderstood?

I've checked these steps

http://help.clickdimensions.com/steps-to-check-before-using-form-capture-records/

http://help.clickdimensions.com/integrating-forms-using-form-capture/

If more information is needed or screenshots, please let me know.