The email system no longer works using a "POP - before - SMTP" protocol. You can send whenever you like, regardless of whether you have recently POPped your mail. To do this you need to enable Outgoing Server Authentication in your mail program. In Outlook, it's under "More Settings" in "View/Change Email Accounts". For info on your email program, check here or see your software help files.
To reduce spam attacks many ISP's - your internet provider - force you to use their Outgoing SMTP mail server.
Here are a few you can try:
Comcast: Outgoing mail (SMTP): smtp.comcast.net
AOL: Outgoing Mail (SMTP): smtp.aol.com
Netscape Internet Service Outgoing Mail Server - smtp.isp.netscape.com (port 25, using a secure SSL connection)
Google Gmail Outgoing Mail Server (SMTP): smtp.gmail.com The Gmail SMTP server requires authentication (use the same settings as for the incoming mail server)
The Google Gmail SMTP Server requires an encrypted connection (SSL) on port 465
Yahoo Incoming Mail Server (POP3) - pop.mail.yahoo.com (port 110)
Yahoo Outgoing Mail Server (SMTP) - smtp.mail.yahoo.com (port 25)
