Captivate 2017 - Unable to retake quiz

t seems to me that you are confusing two levels in the quiz:

1. Question level: you set the attempts to infinite. Normally this means that the learner cannot leave tle quiz unless the question has been answered correctly.
2. Quiz level: it has no sense to retake this quiz, since all questions have to be answered correctly there will never be a failure.

Try to set the attempts on question level to 1. You can keep Continue both for Success and Last attempt. At the end of the quiz the learner will see the score slide with the Retake button since you have Infinite attempts on Quiz level. When clicking that button all questions are reset, the quizzing variables as well and learner can have another quiz attempt.

On quiz level you also have actions On Passing and On Failing Grade. Those actions will be done after clicking the Continue button when the playhead reaches the end of the score slide.

Some more details in this old post which I urgently have to upgrade for the most recent version:

Question Question Slides in Captivate - Captivate blog

It is the most visited post on my blog.