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 ('2ff8eb6a8077b49caa14f5a5c58b22fa', -1, 1539680286, 1539680286, '36c6d41e', 2, 0, 0)

Line : 187
File : sessions.php