SMTP (Simple Mail Transfer Protocol) is a protocol for sending email messages across the Internet. It is used in conjunction with both POP3 and IMAP, protocols that enable you to download messages from a mail server to your computer. SMTP is used for outgoing mail while POP3 and IMAP are used for incoming mail. AdvancedNetworkHosts does not support IMAP.

SMTP authentication is a way to ensure that outgoing email messages are really being sent from you and not from someone else who has gained access to your SMTP server, such as a spammer.

If you are using an ISP's mail server to send mail instead of AdvancedNetworkHosts's mail server, each time you log in to your email client you will need to be authenticated before you can send mail.

To be authenticated by the SMTP server:

1. Establish a connection to the Internet.
2. Launch your email client.
3. Ensure that there is no outgoing mail in your outbox.
4. Log into the POP (incoming) mail server to check your email.
5. Once you have checked your incoming mail, you will be authenticated for the entire time that you remain connected to the Internet.

If your SMTP access is denied even after logging in to the POP mail server, you should contact your Internet Service Provider (ISP). It is possible that they are not allowing relay to an outside SMTP server. Some ISPs are implementing this feature in order to prevent spamming.

If this is the case, you can work around the problem by using your ISP's SMTP (outgoing) mail server instead of AdvancedNetworkHosts. This change will not affect the appearance of your outgoing email messages. When recipients reply to your email messages, they will still see your domain email address.