[Answer]-Django form and field validation does not work?

Your form should be submitting to itself. Meaning, if the form is on /union/contact/, you should be POSTing to /union/contact/. Currently, you have it submitting to a different view/url.

The problem is arising because your form processing is happening in the FormView, not at your success_url(). You need to POST to the view that is actually responsible for the validation of the form (in this case, your ContactView at /union/contact/).

As a side note, it would probably be better to modify the action of the form to use {% url 'your_form_url_name' %}, as opposed to hard-coding the url into the template.