I am running Widows XP Pro with SP2. I have disabled my AVG anti virus,switched off Windows Firewall,tried sending in Safe Mode, reinstalled Outlook Express but still get the same message - "An unknown error has occurred. Account:'pop.ntlworld.com', Server:'smtp.ntlworld.com', Protocol:SMTP, Server Response:'421 aamtaout03-winn.ispmail.ntlworld.com connection refused from [xxx.xxx.xx.xx]', Port:25, Secure[SSL]: No, Server Error: 421,Error Number 0x800CCC67" NTL insist it is a fault with the computer because I can send an e-mail via webmail. I rang the NTL PC helpline (at £1.00 per minute) who insist it is not a PC fault because the error message states "connection refused". Can you please help !