I can't send mails using Outlook Express and Microsoft Outlook
I am using Windows XP Pro OS connecting to a mail server using linux in a centos flatform. Using Thunderbird as a client got me no problem in receiving and sending mails using but when I try to configure my email using Microsoft Outlook or Outlook Express I can not send mails and this error occurs.
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 'Sample Mail', Account: 'mail.account.com', Server: 'smtp.account.com', Protocol: SMTP, Server Response: '504 5.5.2 <walk2>: Helo command rejected: need fully-qualified hostname', Port: 25, Secure(SSL): No, Server Error: 504, Error Number: 0x800CCC79.
Please help me solving this problem.