If the operation is successful, the error number of 0 is appended to the error string. If a calendar cannot be accessed or is missing, the error number is appended to the error string.
The following failure codes can be returned:
X-NSCP-WCAP-ERRNO:1 - Session ID timed out or Invalid session ID
X-NSCP-WCAP-ERRNO:28 - Command failed. User denied access to a calendar
X-NSCP-WCAP-ERRNO:29 - Command failed. The calendar does not exist in the database
X-NSCP-WCAP-ERRNO:56 - Fetch deleted components failed
X-NSCP-WCAP-ERRNO:57 - Success but partial result