Wordpress.com: Form is stuck on please wait after submit.

I've created a New Contact Form, 3rd party published via Wordpress.com. It displays correctly, I populate it and after clicking 'Submit', it just diseplays 'Please wait...'. 

Should I use a different publish feature?

We apologize for any inconvenience this has caused you.

Kindly remove the script part in your embed code and leave only the iframe code.

ex.

Please try that and let us know how it goes.