Invalid recurring appointment start date: This error indicates that the calendar item is recurring and has an invalid start date. This typically happens for old appointments which have become corrupted, or for appointments which were incorrectly created by a third-party application (ex: sync or CRM application).
Resolution:
We recommend the following:
- Log the subject of failed items
- Retry failed items (subjects will be logged)
- Review error logs to identify the offending calendar items
- Fix the start/end date (ex: open and save each calendar item)