phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('9c97e02853f888dea284b5ed2f9116e4', -1, 1490448534, 1490448534, '36c54a89', 2, 0, 0)

Line : 187
File : sessions.php