Message when false password

Hi Community,

I have installed the plugin and it works fine, when I enter the right password.

When I enter a false one, then the following message occurs on the screen:

Warning
: hash_equals(): Expected known_string to be a string, bool given in
/homepages/path_2_my_homepage/wp-content/plugins/password-protected/password-protected.php
on line
308

How can I fix that?
Best
relativhammer