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 ('48434b1331657d211bc6c13b450cb4bb', -1, 1728600692, 1728600692, '2cc05fa1', 18, 0, 0)

Line : 189
File : sessions.php