* @param receiver who was the recipient of the erroneous request.
* @param stanza the stanza of the erroneous request.
* @return the generated stanza.
*/
public Stanza generateNoSuchSubscriberErrorStanza(Entity sender, Entity receiver, IQStanza stanza) {
XMLElement notSubscribed = createXMLElement(NOT_SUBSCRIBED, NamespaceURIs.XEP0060_PUBSUB_ERRORS);
return errorResponses.getStanzaError(StanzaErrorCondition.UNEXPECTED_REQUEST, stanza, StanzaErrorType.CANCEL, null, null, notSubscribed);
}