Kaltura_Client_Exception thrown

Invalid KS "MWVjYWI1NGU4MzQwNGY2YWJjZjgxZGE0YmIwMjcxNzhkZGUxNmRjMnwxMDE7OzE0OTA5NTIzNDc7MjsxNDkwODY1OTQ3Ljg1MDU7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"