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 ('3b3f20b87db42950b932be3f13f121b8', -1, 1462792663, 1462792663, 'cff1e791', 4, 0, 0)

Line : 187
File : sessions.php