From the log file
11/8/2016 11:06:42 AM: QVX_UNEXPECTED_END_OF_DATA: INVALID_SESSION_ID: Invalid Session ID found in SessionHeader: Illegal Session. Session not found, missing session hash: gQcX11vhnyqmRYObzscAtw==
11/8/2016 11:06:42 AM: This error usually occurs after a session expires or a user logs out.