Not sure if this is related to you, but many ISPs are blocking what is called "Port 25" which is the port used to send e-mail. They are doing this to cut down on the amount of spam that is sent from their networks.
Tiscali use a port 25 block. When, your Internet connection was not via Tiscali.
As a general rule, the owner of the port 25 SMTP server you are
using must be the same as the entity providing your Internet
connection at that moment. For more on this policy, see
http://www.postcastserver.com/help/Port_25_Blocking.aspxThe available workarounds when sending away from your home
ISP are as follows:
1. Use webmail for sending (via your browser).
2. Ask your home ISP if they support a port other than '25' for SMTP.
3. If you use the same away-from-home connection frequently,
substitute the SMTP server belonging to that connection (O2).
4. If you frequently send from multiple locations, get a free Gmail account,
configure it for POP access, set it up in Windows Mail, and use that for
your sending chores. Gmail uses port 465 for SMTP, which is not blocked
like port 25 is.
