Cannot retrieve saved course

I began creating a sample course.  Three slides I was unable to move a content box onto the slide.  So I pressed Save and now cannot retrieve my work at all.  Clicking Edit gives me:

Semantics error: TypeError: Cannot read property 'question' of null



falcon's picture

Could you export that content as an H5P and upload it here? Do you remember exactly what you did when it stopped working? What kind of content where you trying to drag to the slide? When did you last upgrade your content type libraries?