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 ('768c8866c4bc6ecce01a94250ad6e637', -1, 1558394644, 1558394644, '36a3147b', 5, 0, 0)

Line : 187
File : sessions.php