You write that it started a few days ago? The plugin was last updated 2 months ago.
This means that there is a conflict with another plugin that was installed recently. Try disabling recent plugins to identify the culprit.
This is not true. Something is installed on your site that conflicts with the plugin. For example, the dark design of the admin panel or plugin or theme.
I can investigate the problem if you give me access to the admin panel in private messages here on the forum