Some internet providers block port 25 (as a precaution against spamming) to all ip's except their own mailserver. If this is the case (try to connect through telnet port 25 on your server) there are two solutions:
1. have your server listen on another port (e.g. 2525) for SMTP (and configure Outlook Express accordingly)
2. use your internet provider's mailserver (e.g. smtp.yourprovider.com) |