Why doesn't my learnpress page show?

I want to create a e-learn platform with WordPress. I installed LearnPress plugin and I added several Courses and Lessons among the courses. I added dummy content for each lesson. However when I want to view a Lesson (doesn't matter which one) the page is freezed in a loading loop, like in the snapshot below:

In the console I receive the following error:

Uncaught TypeError: Cannot read property 'top' of undefined

at p (main.min.js:94)
at HTMLDocument.<anonymous> (main.min.js:182)
at i (jquery.js:2)
at Object.fireWith [as resolveWith] (jquery.js:2)
at Function.ready (jquery.js:2)
at HTMLDocument.K (jquery.js:2)

The error is pointing to an undefined element but why is giving me this error since I didn't modify the code inside the plugin. I followed other forum questions related to this issue but couldn't find any ansewer. What am I missing? Any suggestions? Thx