Some (but not all) of my question slides display "You did not
answer this Q completely" and do not allow the user to answer. I
originally copied some question slides for uniformity, but it has
occurred to me that maybe that was a bad idea so I have been
deleting and re-creating them. However, it still happens.
Edit one of the question slides where you have a problem and
see what parameters have been set for a full correct answer. You
will probably find some arbitrary piece of incorrect information
there that is messing you around.