On those computers and with those browsers (Chrome, Firefox) where I have already checked the test and my name and email is inserted it is not possible to enter new data. The fields seem locked. I have emptied the browser's cache and deleted the quiz records in Ariquiz, but that did not help.
Now I have tried it with Internet Explorer, that I haven't used for that purpose yet. There the problem does not appear.

I had to delete the ariquiz cookie in my browser, then it worked