a client just emailed me this error she keeps getting when attemtping to sends emails, some get through most don't, she receives emails fine:
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was [email protected]'. Subject 'Re: some topic', Account: 'client's name', Server: 'smtp.wanadoo.es', Protocol: SMTP, Server Response: '550 You are blacklisted [host]', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
"youo are blacklisted" jumps out of that error message.