Kaltura_Client_Exception thrown

Invalid KS "MWM1YmZhNjk3MjRiNWJkNzI5MmI2YWNjMDNiNTk5NDQ0NGUxZGMwN3wxMDE7OzE0OTMxMjAzMTg7MjsxNDkzMDMzOTE4LjM3MjY7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"