phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('e407a81e42a66ec59986765dcdc903cb', -1, 1462796044, 1462796044, 'cff1e791', 4, 0, 0)

Line : 187
File : sessions.php