When you disable the setting for One Attempt, students may retake an active quiz many times. If a student logs out during a quiz, they may login again and restart the quiz. Free accounts, and PRO rooms without rosters, can not limit quiz attempts and the setting is disabled by default.
When you enable the setting for One Attempt, you effectively ensure that the student can only complete the quiz once; students will not be able to retake the same quiz multiple times. However, if a student logs out while the quiz is running, they can log back in and continue the quiz from where they stopped.
Enabling One Attempt is only available to teachers with PRO accounts and is limited to rooms with rosters. The setting is enabled by default in rooms with rosters.
In the Settings section, enable the One Attempt toggle. This toggle is enabled by default for quizzes run in rostered rooms.