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 ('12f69d50c6528a72e9ec9933f3624d7e', -1, 1539877640, 1539877640, '36e09618', 9, 0, 0)

Line : 187
File : sessions.php