Calendar access to anonymous users

Hello everybody,
I'm just about configuring the calendar-module, and nearly everthing is ok so far. But there is one problem I don't get solved, I looked everywhere for this setting, but didn't find it:
An anonymous User sees always just an empty calendar. Although I granted access also to anonymous, they see the calendar, but it's completly empty.
Can anyone help me, i can get the events visible to all users?
Thank you very much,
llkks