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 ('257779f9c49daab8e1c9c005c9317b03', -1, 1571222117, 1571222117, '22ccbf1f', 20, 0, 0)

Line : 191
File : sessions.php