Key error

Trying in every possible way to restore the work of the theme along with the functions that this plugin gives, I constantly have critical errors in some key in the file

Warning: Undefined array key "page" in /sites/vicka.ru/wp-content/plugins/ocean-extra/includes/panel/theme-panel.php on line 45

Warning: Undefined array key "page" in /sites/vicka.ru/wp-content/plugins/ocean-extra/includes/panel/demos.php on line 944

The problem starts here, the plugin adds functionality to the theme, not the theme, when I wrote about the problem https://wordpress.org/support/topic/photos-not-adding-to-gallery/

Actually, I have problems with the plugin, because of which photos are not displayed and added to the field that the plugin creates in order to create a photo gallery.

Sometimes this error appears after all sorts of attempts to reset the site settings (like WP Reset or Advanced Database Cleaner) and reload the theme and plugin.