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 ('b4dadbf1c1d1a6322191db4c7a1ac5c0', -1, 1561050334, 1561050334, '3655a2d5', 28, 0, 0)

Line : 191
File : sessions.php