This error can occur if the course is unknown to our servers. This is an issue that your instructor needs to correct. Here is an explanation of the problem that you can copy/paste into an email to your instructor:
Dear instructor,
I could not complete this exam because I encountered an “invalid profile” error. This means that there is a problem with the exam URL. The following instructions are from Respondus Support:
This issue usually occurs if the LockDown Browser Dashboard tool used by faculty hasn't been opened for the course since it was first copied (or since this specific exam was copied into the course.) Please open the LockDown Browser Dashboard tool one time for the course. You may see errors for the quiz. If so, click the "Fix it" button. This should correct the problem.
Thank you,