phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('4a8c5e0e05c9e7ad47b04572c486c5f1', -1, 1571333706, 1571333706, '12cc3028', 27, 0, 0)

Line : 191
File : sessions.php