Did you do the exam on mobile or desktop? Also, what browser were you using?
Not sure how you'll get back to me, it never asked for an email or anything.
The no-script might be at fault though. You might consider not using any CDN for scripts, only host locally.
I did not try again because I don't have a prescription (I submitted an image saying "no prescription"), and I realized it can't do anything for me (I just wanted a checkup basically - just tell me how I did on the various sized letter thing).