If you are getting anything like the following errors:
Call to a member function setAttribute() on null in /wp-content/plugins/email-before-download/includes/class-email-before-download-form.php on line 51
or
Call to a member function insertBefore() on null in /wp-content/plugins/email-before-download/includes/class-email-before-download-form.php on line 61
then it’s most likely due to the plugin assuming that you wrap your inputs with p tags. So if you change your form to use p tags then it should start working again. :/
The plugin assumes you wrap your inputs with p tags. If you wrap them with divs like I did then you will get errors similar to this. :/