Error (0x800CCC7D)

I am a bit stumped and was wondering if anyone can help.

I have just set up a new computer, W8.1, Outlook 2003 and all was working yesterday. However, today I cannot send any e-mails. I get this error message: Sending' reported error (0x800CCC7D) : Your outgoing (SMTP) server does not support SSL-secured connections.

Yet when testing the account settings, the sending does work, no errors reported.

I checked the setup (port 465, SSL), I checked the firewall (all traffic from Outlook 2003 allowed). All seems OK and like I said, it worked on the previous (now defunct) computer and it worked on this computer yesterday.

Any ideas what might be wrong?

Thanks.

Suzy