By default, Blackboard allows for a single test attempt. If your instructor enabled multiple attempts, check the test description to see if the instructor provided this information.
If you are kicked out of a test or experience issues within the test, please take a screenshot of the issue. Email the instructor, attach the screenshot and explain what happened. You may also contact Blackboard Support in case the instructor requests documentation. Please note that your instructor is the only one who can authorize an additional attempt.
Screenshot on Mac:
Screenshot on PC: