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 ('3ed67d27a039b6f74c8c2ffa6d50fd73', -1, 1539846096, 1539846096, '36a16418', -9, 0, 0)

Line : 187
File : sessions.php