Kaltura_Client_Exception thrown

Invalid KS "MWNiZjZmNGVjZGE0YzU2MWEzMWNlZjBmMWUxNzI0MDBmYTgxM2RiZHwxMDE7OzE0NzUwMzYxNzg7MjsxNDc0OTQ5Nzc4Ljg1NjM7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"