Kaltura_Client_Exception thrown

Invalid KS "MTZkZmM1NzdmN2RiODVjYmI5ZjFjZDE2Njc4ZjZlYjdmNjJlYjVjMXwxMDE7OzE0NzUwMTY2NDA7MjsxNDc0OTMwMjQwLjkyNTU7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"