outgoing mail failure

I have recently set up windows mail and I can receive mail but not send it. I
have tried some of the previous suggestions in similar threads but to no
avail. I get the following error message:

-- The connection to the server has failed. Subject 'test', Account:
'tiscali', Server: 'smtp.tiscali.co.uk', Protocol: SMTP, Port: 587,
Secure(SSL): No, Socket Error: 10060, Error Number: 0x800CCC0E

Janie B