If your ISP requires authentication for email sending and receiving, use these values:
mail server = pop3
incoming pop3 email server = mail.rc.net
outgoing smtp email server = whatever smtp outgoing email server name your ISP gives you to use.

Check the box that says "my server requires authentication" or "Use name and password" and then enter your ISP-provided "account name" and "account password".

Note: You may have to set the server port number for outgoing mail (SMTP) to a different number such as 465.
Note: You may also have to check the box that says "this server requires a secure connection" for the outgoing mail (SMTP) server. Do not check that same box for the incoming (POP3) server.

Do Not Check the box that says "Log on using Secure Password Authentication".

For even more detailed setup information, including screen shots, click here

AT&T/Yahoo customers click here for information on "send errors" or "553 errors".