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 ('cd8283ba84de453687c28a906948d8c7', -1, 1553546804, 1553546804, '22e42a19', 29, 0, 0)

Line : 187
File : sessions.php