exim 550 relay not permitted Webuzo Squirrel Fix

exim 550 relay not permitted error can be happened when you set squirrel mail config wrong , especially if you set 'localhost' as imap / smtp server.
Solution: edit config.php to be your true dns host domain.

Change SQUIRREL MAIL CONFIG:
/home/soft/www/squirrelmail/config/config.php

edit :

to become :

$smtpServerAddress = 'smtp.yourdomain.com';
$smtpPort = 25;
$use_smtp_tls = false;
$smtp_auth_mech = 'none';
$smtp_sitewide_user = '';
$smtp_sitewide_pass = '';
$pop_before_smtp = false;
$pop_before_smtp_host = '';

$imapServerAddress = 'imap.yourdomain.com';
$imapPort = 143;
$imap_server_type = 'dovecot';
$use_imap_tls = false;
$imap_auth_mech = 'login';

Then check your DNS entry for your main domain.

should  have:

imap 14400 IN A 192.6.162.148

smtp 14400 IN A 192.6.162.148

whereas 192.6.162.148 is your public ip of your vps.

Also, set Email Settings in Webuzo admin interface to use Exim smtp server

username: arealuseraccount@yourdomain.com

password: 12345678

port: 25

host: smtp.yourdomain.com