ANTISPAM_YAHOO

The recipient's SMTP blocks your mail because one of these reasons:
- Your HeloDomain in server.tab is no real domain name
- You run XMail from a dynamic IP address range
- You are in a cable modem IP range
- Your SMTP is an open relay
- You or your ISP are blacklisted by an antispam database.
  In that case search the SLOG for details about the blacklisting 
  service and see if it is possible to clear your entry from that list.

To check your relay, use the following services:
- http://mail-abuse.org/tsi/ar-test.html 
  (just telnet to relay-test.mail-abuse.org from your server) 
- http://www.antispam-ufrj.pads.ufrj.br/test-relay.html 

To check, if you are listed in some antispam database, visit
http://openrbl.org

To secure XMail:
- Set smtprelay.tab to the scope of your subnet if your want your LAN users to relay. 
  If not, just clear that file.
- Do NOT use mail-auth in your server.tab. 
  This blocks all mails from other SMTPs, because they cannot authenticate with your system. 
  This authentication scheme is meant for private or complex public infrastructures. 
  So make sure that #"SmtpConfig" "mail-auth" is commented out in your server.tab.
- Make sure that "EnableAuthSMTP-POP3"[TAB]0 is NOT commented out with a # in your server.tab.
- Enter "0.0.0.0"[TAB]"0.0.0.0"[TAB]"ALLOW"[TAB]1[ENTER] in smtp.ipmap.tab
- Set "SMTP Server requires authentication" on your mail client.

From now on 
- XMail only allows authenticated users to send mail.
- It is still open to receive mails that are for its own domains.
- It won't allow any spammers to use it as a mail relay (as long as they havn't got a valid user account)

If this error is caused by your dynamic IP address:
Forward mails to that domain to your ISP's SMTP with following entry in smtpfwd.tab:

"target_domain.com"[TAB]"your_isp_smtp.com"[ENTER]

If your ISP's SMTP needs authentication, you need to create a file in /MailRoot/userauth/smtp.
See the Xmail Manual for details (chapter "SMTP CLIENT AUTHENTICATION")