There are a few reasons why a proctored or timed exam you've completed may be scored as zero:

• Exam scores are hidden
• The proctored exam did not pass all proctoring requirements (Read more here)
• The course is archived

Scores are hidden

In some special, advanced-level courses (like MicroMasters courses), the course team may configure the exam's score to be hidden until the due date has passed or always hidden.

Your certificate will still be available based on the true score that you earned on the exam.

The proctored exam attempt didn't pass proctoring rules and requirements

Proctored exams are reviewed by a secure third party to ensure the learner followed the exam's rules. If the exam was flagged for any reason, you should receive an email notification. You can contact edX Support for assistance appealing this.

The course is archived

In archived courses, the progress score for all assignments and exams won't update. Archived courses aren't active and it's not possible to earn a certificate in archived courses. You can read more about archived courses here.