Kaltura_Client_Exception thrown

Invalid KS "MGZiMWJkZTY5YzFmOTgzMTRjYmUyMWY2ZDA0MDBkNTZiNGViOTI2MnwxMDE7OzE0NzUyMDYzNDk7MjsxNDc1MTE5OTQ5LjgzNTg7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"