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 ('02e10d6b122b4aeb44b0ddd76bff7a07', -1, 1539908724, 1539908724, '365057a6', 16, 0, 0)

Line : 187
File : sessions.php