If your exam window closes, and you have time remaining, this may have been caused by a setting enabled in the assessment.
The 'Force Completion' setting does not allow students to return to the assessment after the window is closed, even if the student did not run out of time. This means that once a student begins a quiz, he/she has to finish it within the same window where it was first opened in. Please contact your course professor directly
for more clarity on this, or contact our FIU Blackboard Support Services
department for further assistance.