Lessons doesnt load

I created some lessons and after this I created a course. When I try to add the name of the Module on the course page it keeps loading and after some minutes presents an error I’m having trouble to get the lessons loaded.

Screenshot: https://ibb.co/XYw0s9b

I tried to disable all plugins, update the permalinks (in post name) and looking for js errors in the console (in the lesson and in the course edit)

Any advice to get this fix?