Kaltura_Client_Exception thrown

Invalid KS "MDVjMDFjNzhiZTYwMDNhNDI4YTdhNGNmMDg0NmM3MTA0OTM3MmMyMXwxMDE7OzE0ODA4MzU0MjI7MjsxNDgwNzQ5MDIyLjM3Nzg7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"