Lesson content not showing

Im using Learnpress plugin (They are really rude and don’t offer help unless you buy a theme or add-on) , I created the courses and at first it was working fine, but sometimes the content of each lesson disappears, leaving the course with the title and comments but with no content…. here in this picture you can see the problem https://prnt.sc/1s5nd0y

The page I need help with: [log in to see the link]