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 ('6e9ebb2a394c28d5c2a1280515f44c9d', -1, 1566045238, 1566045238, '22ef933b', 2, 0, 0)

Line : 172
File : /home/rebkell/public_html/boards/includes/sessions.php