I resolved this the other day together with a user: In Vista when Windows Mail fails to connect to the remote SMTP (outgoing) email server returning error code 0x800CCC0B, the reason is that the remote server requires you to have both SSL and SPA enabled:
- Account Properties → Servers → Log on using Secure Password Authentication
- Account Properties → Advanced → Incoming Mail / This server requires a secure connection (SSL)
Managing organized complexity 