Kaltura_Client_Exception thrown

Invalid KS "MTc2OTM4OTI4NjdlYTI1NWUxODAxOGM2ZTI0MTgwYmVlNTMxZTNlZnwxMDE7OzE0OTMwMjEzODU7MjsxNDkyOTM0OTg1LjE0NjE7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"