Hi Carme,
This is what I am seeing as the most recent quiz attempts:
93.33% Quiz: Events Quiz
Score 14 out of 15 question(s)
on Mon, 01 Aug 2016 07:26:14 +0000
—
90% Quiz: DOM Quiz
Score 9 out of 10 question(s)
on Sun, 07 Aug 2016 18:27:20 +0000
Could you try by chance logging in on your phone or another device and trying again? Wondering if that might be connected, or just simply logging in and out again?