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 ('cb13e7c68fa1e425f8f0b9e2af24a323', -1, 1561452209, 1561452209, '03555c8b', 18, 0, 0)

Line : 191
File : sessions.php