When setting up any course, a portal administrator can configure how many times a student may enroll in the course. On the COURSE edit page, this is set up under Additional Data as Enrollment Restrictions. It controls whether or not the student can enroll again and take the course under a new Transcript.
In an Assessment Course, after going into Continue Test Setup, there is a Test setting to determine many attempts a student gets to complete the exam after a failure.
Enrollment restrictions control transcript creation.
Test attempts control how many times you get a chance to take an assessment on the SAME transcript before you get a final completion of Pass or Fail.
To eliminate confusion between multiple enrollments and multiple attempts on the same enrollment transcript, we recommend that assessment courses be set to Once Only and that the Assessment test attempts control the number of tries a person has before the transcript is considered finished.