Kaltura_Client_Exception thrown

Invalid KS "MTlhOGU3YmY2YzE1YWI3OTQ0ODk4N2Y4MTY3YTc1YTA1YzE2Mjk3MXwxMDE7OzE0ODExMTk2NDA7MjsxNDgxMDMzMjQwLjc5ODk7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"