addRecurrenceRule fail

[Xiahaiquan]

HI. I have a problem。when I used the manager add Recurrence rule to Event. I get a issues. that can't
add event to the calendar.

let rule = EKRecurrenceRule.init(recurrenceWith: .daily, interval: 1, end: nil) event.addRecurrenceRule(rule)

that is debug info: Error Domain=CalendarError Code=999 "Unknown Error" UserInfo={NSLocalizedDescription=Unknown Error, NSLocalizedFailureReason=An unknown error ocurred while trying to sync your calendar. Syncing will be turned off.}

is everyone has this issues?