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 ('51072f21a8a98ccf5cff9deb1a27bef0', -1, 1566593628, 1566593628, '22ecbed8', 2, 0, 0)

Line : 187
File : sessions.php