Message Wont Send, Says Error.

Here is the Error message it gives me everytime i try sending the message:

An unknown error has occurred. Subject 'Re: purses i made!!', Account:
'', Server: '', Protocol: SMTP,
Server Response: '421 Cannot connect to SMTP server
(, connect error 10060', Port: 25, Secure(SSL): No, Server
Error: 421, Error Number: 0x800CCC67

Please help ASAP.