If you are connecting to the internet with another ISP (i.e. NetZero, Earthlink, etc.) you can NOT
send e-mail out using Adelphia's outgoing (SMTP) email server while using the other ISPs connection. Sending email through another ISPs outgoing email server like this is called "relaying", which is blocked by Adelphia and will generate an errors such as the following:
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was '******@netzero.net'. Subject '', Account: 'mail.adelphia.net', Server: 'mail.adelphia.net', Protocol: SMTP, Server Response: '550 relaying mail to netzero.net is not allowed', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
To send mail using Adelphia's outgoing (SMTP) email servers you must be using your cable modem connection provided by Adelphia or the webmail access at »www.adelphia.net
Most other major ISPs also have similar "relay" blocking policies. The solution to this problem is to use the outgoing (SMTP) email server of the ISP you are using to connect to the internet.
See this Microsoft Knowledge Base Article for more information:SMTP Relay Blocking Error Sending E-mail
last modified: 2005-11-10 21:56:29