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 ('1afc2a3d73f02f41c64313a706381b50', -1, 1539731248, 1539731248, '36c60f14', 16, 0, 0)

Line : 445
File : sessions.php