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 ('9ef7995e4a812309e43fca1f85dde521', -1, 1556200985, 1556200985, '035080c4', 1, 0, 0)

Line : 172
File : sessions.php