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 ('9a7b8563c0eae1401cd81dc76864c57f', -1, 1531805852, 1531805852, '36a6e423', -4, 0, 0)

Line : 187
File : sessions.php