"Anonymous vote rollover" 2 days, 4 Days, 1 Week or Never not working.

Hi,

i'm using voting api 7.11 and plus one.

"Anonymous vote rollover" 2 days, 4 Days, 1 Week or Never not working.
If i select "Anonymous vote rollover" 2 days, 4 Days, 1 Week or Never at the "voting api" setting interface
then nobod can vote anymore. Its showing "You already voted" at the Voting Button.

I need to ensure that noboy is voting twice for my client.

Thank you in advance.