Form never submits, just spins forever

Using 2.4.4 version of plugin. The form (http://telnexus.com/wp-content/uploads/SF-plugin-form.png) is almost identical to the html form from Salesforce which works, but the plugin never submits. I don’t get error message or completion message. The page with the forms is: http://telnexus.com/affiliate-program-enrollment/

Help!

Here’s the html code that does work just fine:

<form action="https://www.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8" method="POST"><input name="Campaign_ID" type="hidden" value="70140000000wVwj" />
<input name="member_status" type="hidden" value="Inquired" />
<input name="oid" type="hidden" value="00D40000000N0MV" />
<input name="retURL" type="hidden" value="http://www.telnexus.com/thank-you" />
<!--  ----------------------------------------------------------------------  -->
<!--  NOTE: These fields are optional debugging elements. Please uncomment    -->
<!--  these lines if you wish to test in debug mode.                          -->
<!--  <input type="hidden" name="debug" value=1>                              -->
<!--  <input type="hidden" name="debugEmail" value="vern@telnexus.com">       -->
<!--  ----------------------------------------------------------------------  -->
<label for="first_name">First Name:&nbsp; </label><input id="first_name" maxlength="40" name="first_name" size="20" type="text" />

<label for="last_name">Last Name:&nbsp;  </label><input id="last_name" maxlength="80" name="last_name" size="20" type="text" />

<label for="email">Email:&nbsp;  </label><input id="email" maxlength="80" name="email" size="20" type="text" />

<label for="phone">Phone:&nbsp;  </label><input id="phone" maxlength="40" name="phone" size="20" type="text" />

<input type="submit" name="submit"/>

</form>

https://wordpress.org/plugins/salesforce-wordpress-to-lead/