Using Windows Mail in Vista for some time, when it suddenly started timing out while sending mail , although I could receive email just fine. The error message had the usual Port 25 Secure(SSL) 0×800CCC19. So I tried switching off the AV scanning and deleting Pop3uildl.dbx , but that didn’t work. I ended up searching regarding this error and end up finding that it’s an issue with Vista directly. Trying these steps will usually help resolve the issue;

1. Go to the Vista start menu and type cmd
2. The search results will display a program titled cmd
3. Right-click on the link and select “Run as administrator”
4. type “netsh interface tcp set global autotuning=disabled” without
the quotatioin marks
5. Test your POP account and see if you can now download your mail.
6. If nothing changes, re-enable the autotuning feature by typing
“netsh interface tcp set global autotuning=normal”

Hope this helps you.