Page redirects to a blank page

When I follow the steps from the youtube video, and when I go to click, Save and Generate Feed; it then redirects me to:

https://mc-salesllc.com/wp-admin/admin.php?page=webappick-product-feed-for-woocommerce%2Fadmin%2Fclass-woo-feed-admin.php

This page shows up as blank. When I go into, Manage Feeds, it shows that I have no feeds available..