Kaltura_Client_Exception thrown

Invalid KS "MTVlNjg3NjYwMmNhOWVmZDA0NDliNDMyMjc3YWYyNDJjNmQ1MTM1OHwxMDE7OzE0OTMyMzg0NzA7MjsxNDkzMTUyMDcwLjQ1OTQ7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"