Recently I have subscribed to a VPN connection. While connected to the VPN, I tried to send email using my Outlook Express, I recevied an error message:
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'firstname.lastname@example.org'. Subject 'test11.11', Account: 'mail.xxxxxxx.com', Server: 'smtp.xxxxxxx.com', Protocol: SMTP, Server Response: '550 5.7.1 <email@example.com>... Relaying denied. Proper authentication required.', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
It just refused to send out my email. But once I disconnect myself from the VPN and connect just with my normal ISP internet connection, I was able to send the email without problem.
After doing some research, I came to a solution. All I need to do is to set my out going Mail [SMTP] port to "587'" instead of the usual "25".
And yes the mail sent out without any problem.
David Kou Online