Dear @alekscupid,
Thank you for the topic.
We have checked and noticed that everything works fine in this regard on our end.
Please provide us with the link, where the given quiz is located so that we can check, understand what is the problem, and help you as soon as possible.
Also, please check the following case:
Whether the quiz with the particular ID, the shortcode of which you have inserted in the post/page can be found in the Quizzes List table or not.
Please note, that the message “Wrong shortcode initialized” is being displayed only when there is no quiz with that particular ID.
Besides this, please let us know whether you are using a Cache plugin or not on your website.
The issue may be connected with the cache as well.
For instance, the user can be logged in and in the case of having the cache plugin, the quiz will be displayed (most presumably you don’t have the particular quiz (probably you have deleted it)).
While in the case of the guest mode, the cache is not being saved/stored and you see the real view/state, that is you don’t have the particular quiz.
Looking forward to your reply.
Thank you.