phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 2

INSERT INTO mex2mex_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('f5b7055343cfdb7cc505d680cdbebd81', -1, 1397728663, 1397728663, '36518159', 0, 0)

Line : 170
File : sessions.php