Thank you for reporting this issue @jorgeabrantes.
After installing LearnPress in my development environment I can confirm this issue.
Namely the code in this plugin that checks whether the current page contains a Protected Video “block” or “shortcode” is failing. This is preventing the Protected Video assets from loading.
I can’t find a good generic way to check the contents of custom LearnPress “lesson” posts in order to check for the shortcode or block.
So, instead, I have now changed Protected Video to load the necessary JS/CSS assets it needs on any “custom post type” pages. This seems to be the only reliable way to ensure Protected Video assets are loaded on these non-standard type pages, such as LearnPress lessons.
Anyway, this should be fixed now in plugin version 1.8.1 if you’d like to test and confirm this. If so, a review would be appreciated!