The message could not be sent. The authentication setting might not be correct for your outgoing e-mail [SMTP] server. For help solving this problem, go to Help, search for "Troubleshoot Windows Mail", and read the "I'm having problems sending e-mail" section. If you need help determining the proper server settings, please contact your e-mail service provider.

The rejected e-mail address was "MY EMAIL ADDRESS". Subject 'test11', Account: 'pop-server.neo.rr.com', Server: 'smtp-server.neo.rr.com', Protocol: SMTP, Server Response: '530 Authentication is required before sending [R0107005]', Port: 25, Secure(SSL): No, Server Error: 530, Error Number: 0x800CCC78

I had no troubles until last week now I cannot send anything out.  I deleted all old emails in Sent, Outbox, Deleted folders with no help.  My e-mail servers and passwords have not changed in years ?

Using Vista with Windows Mail