Every SMPT server on my Virtualmin installation gives this error. I've googled around and see that this is a fairly common problem, but I don't know how to fix it after reading. I did read that the output of posfconf -n was helpful in solving the problem, so here it is:
[root@server ~]# postconf -n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
allow_percent_hack = no
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = all
mail_owner = postfix
mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME
mailbox_size_limit = 0
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost, server.chrsmckvps4.info
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sender_bcc_maps = hash:/etc/postfix/bcc
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
unknown_local_recipient_reject_code = 550
virtual_alias_maps = hash:/etc/postfix/virtual
[root@server ~]#
Does the mail server name you use as smtp server resolve to your servers ip address? if not try using your ip address as smtp server in your favourite mail client.
Howdy,
You may also want to check your mail log for any errors... you can find that in either /var/log/maillog, or /var/log/mail.log
I'm able to connect to port 25 on your mail server, I don't receive any kind of error when doing that -- so the key is going to be either with any errors you're seeing in the logs, or the specific settings being used in your mail client.
-Eric