phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO forum_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('54dd7918373e88bcf2394a52325e54c7', -1, 1540135212, 1540135212, '36e05922', 3, 0, 0)

Line : 187
File : sessions.php