You may get the error message when trying to send email:
- "The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'test@example.com' . Subject 'Ski trip', Account: 'Test', Server: 'smtp.server.xxx', Protocol: SMTP, Server Response: '550 relaying to prohibited by administrator', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
This problem happens because Outlook Express was configured to use Secure Socket Layer (SSL), which some providers do not use.
To repair this problem: