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 ('8a99835ca7df477c3f33ba9cf0cc88d8', -1, 1558391301, 1558391301, '36a3147b', 3, 0, 0)

Line : 187
File : sessions.php