You must be logged in as a teacher on a paid account or school trial to view quizzes. If you are trying to view a quiz but get a message that you can't view it, there are a few reasons you may be seeing this message:
1. You are not logged in. If this is the case, log in and try to view the quiz again.
2. You are in a trial. Trials do not always allow quiz content access. For more detail on different access types, see this article.
3. You are logged in as a student. Check that you are not logged in as a student. Individual student users cannot see quizzes until they are assigned. Shared student usernames can never see quiz content.