The reasons for the target error.
||An attempt was made to modify or create a CustomFieldValue for a CustomField that does not exist.|
||An attempt was made to create a new value for a custom field that is inactive.|
||An attempt was made to modify or create a CustomFieldValue corresponding to a CustomFieldOption that could not be found.|
||An attempt was made to modify or create a CustomFieldValue with an association to an entity of the wrong type for its field.|
||The value returned if the actual value is not exposed by the requested API version.|