Kaltura_Client_Exception thrown

Invalid KS "MTc0NThiNzYxMGFlYzliMmQ2ZWZkYzlmZjQxYzY1NDM2ZWQ3Nzg5MHwxMDE7OzE0OTYyMDIxMjE7MjsxNDk2MTE1NzIxLjY2MjE7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"