Relay Access Denied - Mail bouncing

[unixfox]

I don't know what has happened here but nobody can receive e-mails. The sender gets the following message returned to them:


SMTP error from remote mail server after RCPT TO:<user@mydomain.com>:
host mail.mydomain.com [xx.xx.xx.xx]: 554 <user@mydomain.com>:
Relay access denied

What the heck is wrong? Thanks

[till]

1) Is the domain mydomain.com listed in the file /etc/postfix/local-host-names?
2) Are these lines in your postfix main.cf file:

virtual_maps = hash:/etc/postfix/virtusertable
mydestination = /etc/postfix/local-host-names

3) If you are sending mails and you are getting this error, make sure that you enabled SMTP Authentication in your email client. In outlook it is nemd "Server requires authentication".