SMTP error 0x800ccc0f

SMTP error 0x800ccc0f

Today my Zoho emails started failing to send from my XP SP3 PC. I get the SMTP error 0x800ccc0f. They send fine from my Windows 7 PC. Nothing has changed on my XP PC. Has something changed at Zoho? The POP3 works fine. Rebooting and shutting down the anti-virus does not help.