Make sure you have send authentication enabled.
Go to Tools, Accounts, select that account, Properties, Servers.
Enable the "My server requires authentication" option.
Gary VanderMolen, Microsoft MVP (Mail)
Mac thank you I can get mail now but not send any other ideas? I used the
pop-server.insight.rr.com and the smtp-server.insight.rr.com and I get this
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
the proper server settings, please contact your e-mail service provider.
The rejected e-mail address was 'MarianneP@insight.rr.com'. Subject 'test',
Account: 'pop-server', Server: 'smtp-server.insight.rr.com', Protocol: SMTP,
Server Response: '530 Authentication is required before sending [R0107005]',
Port: 25, Secure(SSL): No, Server Error: 530, Error Number: 0x800CCC78