Memrise HTML error in my course

I have created a course in Memrise. Here is the URL to it:

When I try to use the course it works but any time it tries to use either the Speed Review or the Practice Your Listening Skills it gives the following error message:

“Whoops. Could not load the session sorry.”

I have no idea how to fix this. It appears to be an HTML error and this should most likely be directed to the website developers.

When in the course editor I can play back all the audio files and it shows the pictures loaded with no issues.

I am using Microsoft Edge. I tried it on a friends computer running Google Chrome. Same results.

I get the same error message most of the time when I try to begin a “speed review” session on the Middle Egyptian - Hoch Hieroglyphs course. Dev tools shows the ajax request for the session data returning 400.

This is not a problem I have on any other courses, or for other session types on this course. It started happening when I was around 5 levels in.

Another symptom is that when the session does load it often presents only 1-3 words, even when the scheduler has a long list. That is, the suggested session will be “speed review” many times in a row, each time prompting for only a couple words, which gets pretty tedious.

OK I submitted this as a software bug to the developers. hopefully they can fix it.