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 ('99e9d1d8d0b908c2ca1103e1679b9256', -1, 1566650003, 1566650003, '22ec2692', -9, 0, 0)

Line : 187
File : sessions.php