Look for the number of oval to fill in for each contest.

Check the number of ovals you have filled in.

If you fill in ovals for too many candidates in one contest} the scanner will display a message that you have an "Overvoted Ballot."  You can press "Return Ballot" to get your ballot back and correct it, or you can ignore the message and cast your ballot with votes that will not count.

Check your ballot carefully - in some contests, the candidates are listed in two columns.