Allow unregistered users to vote on polls

[XFFA.IR Bot]

I've create a sub forum where unregistered users should be allowed to vote on polls. I applied the following permissions to "Unregistered" user group for this forum:

• Vote on threads/posts (when applicable)
• Vote on Polls

It works without any problems for registered users, but not for unregisted users. What am I doing wrong? Thanks.