phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO pcxhpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('993e68cad92f164b1f3810452ec59517', -1, 1568761364, 1568761364, '03e2f382', 12, 0, 0)

Line : 186
File : sessions.php