Can’t access tools tab

Hi, I just started testing out your plugin.
I would like to use the bulk add watermarks but unfortunately, I get an error 500 when trying to access the tools tab.
I even downloaded the plugin on another wp site that I have and it has the same issue.
I also tried selecting all the images that I want to watermark in Media and then selecting images and then selecting “Watermark” in the bulk actions. It works well but only for a couple of pictures, unfortunately, I have thousands to watermark.
What can I do to watermark all of these images easily?

Let me know if you need more information.

Kind regards