O/G Mail suddenly stopped working - Help !

[SB]

For some strange reason my Windows Vista mail has stopped sending mail. Still
working fine on incoming mail, and I can use web based mail using the same
e-mail address via the same service provider (BT Internet). I've not made any
changes to my account settings, and they all appear to be correct - any
advice gratefully received !

The message I'm receiving is: Your server has unexpectedly terminated the
connection. Possible causes for this include server problems, network
problems, or a long period of inactivity. Subject 'Re:", Account:
'mail.btinternet.com', Server: 'mail.btinternet.com', Protocol: SMTP, Server
Response: '451 See http://pobox.com/~djb/docs/smtplf.html.', Port: 25,
Secure(SSL): No, Server Error: 451, Error Number: 0x800CCC0F

 

[Gary VanderMolen]

"Unexpectedly terminated" is usually caused by interference from an
antivirus program. Which antivirus are you running?
As a minimum, email scanning in the antivirus should be turned off,
although that may not be sufficient to eliminate all bad effects.
In a worst case scenario, your antivirus may need to be uninstalled.

Email scanning in any antivirus should be disabled, for reasons
explained here:
http://thundercloud.net/infoave/tutorials/email-scanning/index.htm

If no improvement after disabling email scanning, consider upgrading
to Windows Live Mail, because it is less prone to suffering bad effects
from overly intrusive antivirus programs:
http://download.live.com/wlmail