'The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was ....... Subject 'that thumbprint', Account: .......', Protocol: 'SMTP, Server Response: '451 http://www.spamhaus.org/query/bl?ip=93.107.74.175', Port: 25, Secure(SSL): No, Server Error: 451, Error Number: 0x800CCC79' comes up when trying to send a message from outlook express and the email address is the same one that outlook express was set up for, my own. I would love to know how to solve this problem. I have recently started using my laptop for outlook express so maybe I have not set up the settings properly. Please helpMichelle2 people need an answerI do too