phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO satshop_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('f1389df38db83b2a6eb9174ff6bebf8d', -1, 1728658624, 1728658624, '2cc87ad6', -1, 0, 0)

Line : 189
File : sessions.php