Problem with login

Hello, there’s a problem with the users ultra login option.
When the plugin is active the login page is empty, so I’ve got to deactivate it from phpmyadmin in order to be able to log into my account and after that I activate it again. Right now I do that, however when I make public my website users will obviously not be able to do that so I really need to fix this.
Please help me, thank you

https://ww.wp.xz.cn/plugins/users-ultra/