phpBB by Przemo : 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 ('9be835a8650372550ba9a5ba7eb199af', -1, 1540167106, 1540167106, '3650bc57', -7, 0, 0)

Line : 445
File : sessions.php