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 ('a90a8fe837f989e9cf7514c415011f8f', -1, 1558923439, 1558923439, '36e2045b', -4, 0, 0)

Line : 187
File : sessions.php