Hello Elisheva,
Sorry for the trouble. Let’s see how we can help.
We have already replied back to you through email but here’s our reply on this.
First please make sure that you do not have any blank questions or answers in your quiz because we’ve found found that this might also cause such errors from few past experiences.
Are you having trouble with this quiz only or all of the quizzes you create? If only this, then there is chance that it might be occurring due to some type of invalid input in this quiz only like blank questions or answers.
Also I am seeing a JavaScript error in the Developer Tools console, so this might also be conflict in between Quiz Cat and your currently active theme or other active plugins.
So we might present with the conflict isolation steps in the next reply if you are not ale to solve the issue with the above steps.
Please get back to us with the information and we’ll see what we can do to help next.
Thanks.