Reply To: Family Entry type

@ Tom

That last message is the issue. Something is throwing a server error 500.

Do the same again but this time, click the Network tab in the browser Console. Before you submit the form, clear the network activity by clicking the circle with a slash thru it. Submit the form and then click XHR in the Network monitor. The last item should be to admin-ajax-php. Click that. After you do there will be a Response tab displayed beside it. What is the response. It should start with Internal Server error 500. Hoe fully more will be there to help narrow down the cause.

Did you suppress the PHP notices and warning like I suggested?