Kaltura_Client_Exception thrown

Invalid KS "MTg0MDI2YTNjNzM5NDVjMmJmYTc2MzhhMTk2YWU3NjA3NTdjYTBiZXwxMDE7OzE0OTYyMzA3NTI7MjsxNDk2MTQ0MzUyLjgyNzE7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"