First try this:
Make sure you have send authentication enabled.
Go to Tools, Accounts, select that account, Properties, Servers.
Enable the "My server requires authentication" option.
Then click on the Advanced tab and change port 25 to 587.
If no improvement, change the server name to mail.bellsouth.net.
If still no improvement, your account may have been migrated to the
AT&T/Yahoo mail platform. Try the settings given here: http://www.att.com/esupport/article.jsp?sid=KB401738
Gary VanderMolen, Microsoft MVP (Mail)
Microsoft MVP program: http://mvp.support.microsoft.com
"MarcC" <MarcC@newsgroup> wrote in message news:C30E5A4B-87C6-41CA-AA80-5FFD0AD8D967@newsgroup
>I have been using Windows mail and no problems until yesterday. Now I can
> download incoming mail but my new messages will not go out. I get the message
> The connection to the server has failed. Subject 'TEST 10', Account:
> 'mail.atl.bellsouth.net', Server: 'mail.atl.bellsouth.net', Protocol: SMTP,
> Port: 25, Secure(SSL): No, Socket Error: 10061, Error Number: 0x800CCC0E
> I can log into Internet Explorer and send messages but not from Windows Mail
> Thank you