password protected page going to blank wp-pass.php

I am trying to add password protection to a SSL secure page as a way to offer a discounted price to special groups. When a person goes to https://kathibrowne.com/blog/discount and enters the password, they end up at a blank screen at wp-pass.php. I found an old post that suggested editing line:
wp_safe_redirect(wp_get_referer());
to
wp_safe_redirect(wp_get_referer() . ‘?’);

but now the discount page doesn’t seem to ever finish drawing up. It isn’t a firefox issue because it did this for me (Mac) and many other people using a variety of platforms.

Any help would be appreciated.