Gets a paginated list of messages that were not sent, ordered from oldest to newest.
|type||string||Required||Only notSent is supported.|
|$pageSize||integer||Number of messageKeys (array elements) to return per response page.|
|lastEventId||integer||Event ID from which you want the response to start. To obtain the initial event ID, submit a request without a lastEventId. The events in the response are listed top to bottom from oldest to newest.|
|200 OK||Success. Review example response.|
|400 Bad Request||Invalid request|
|401 Unauthorized||Failed to pass authorization.|
|500 Server Error||Internal error|