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 ('d02f0db0b61f4b5539b1cf5ad4a6ede3', -1, 1397917720, 1397917720, '36ea3c85', 7, 0)

Line : 170
File : sessions.php