Kaltura_Client_Exception thrown

Invalid KS "MDZjNWNkYzFjMjBiZjVkNzc3MDQ0NjFmMWE1ZjhmZGQxMTBhYjQ4M3wxMDE7OzE0NzUxNTIxNjY7MjsxNDc1MDY1NzY2Ljc3OTg7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"