Remember to Authenticate.
Our SMTP server, what is used to send email, must be authenticated with prior to being able to accept email for relaying. While previously you may have been able to send email by logging in via POP3 first to check your email, now you must specifically authenticate. All email clients will allow for this and it is a simple change. If you are unable to send email through your hosting account, and your ISP or firewall does not block outgoing traffic on port 25, make sure authentication is enabled.
