Not saving to database

Hi, I am working on a WordPress website for a client which is using the wp-favorite-posts plugin. The favorites feature works fine in cookies mode, but when I am logged in (e.g. as an admin user) it is still using cookies, not persisting to the database, so our users do not retain their favorites across different browsers or devices. We have followed all the installation instructions as per your documentation. Is anyone aware of this problem or reasons why it might occur, or things I should check for? I can provide more details if requested but unfortunately am not able to provide a public link, however if a project admin contacts me privately I may be able to provide access.

Many thanks,
Pete

https://ww.wp.xz.cn/plugins/wp-favorite-posts/