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 ('6e304da6414f2437f35ce6e855b52a50', -1, 1490448673, 1490448673, '36c54a89', 2, 0, 0)

Line : 187
File : sessions.php