Dovecot fails to deliver to all mail clients

Hello everyone

I am new to linux and recently created a mail server on a SusE linux 10.2 Machine using POstfix and Dovecot.

Postfix seems to be working fine as mail gets delivered to all user's mail boxes and on checking mail on thbe mboxes it is there. However I am unable to read mail using a client such Kmail, Mutt, Outlook, Outlook Express.

When I use Telnet on port 110 I am able to loging using user's login credentials, but on running the command 'stat' it shows that there is no mail. but mail is there cause I have checked manually and /var/log/dovecot.log shows the following.

dovecot: Jun 19 14:29:08 Info: pop3-login: Aborted login: user=<root>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 14:29:08 Info: auth(default): passwd-file(zwelabantu,10.29.128.164): unknown user
dovecot: Jun 19 14:29:10 Info: pop3-login: Aborted login: user=<zwelabantu>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 14:39:10 Info: auth(default): passwd-file(root,10.29.128.164): unknown user
dovecot: Jun 19 14:39:12 Info: pop3-login: Aborted login: user=<root>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 14:39:12 Info: auth(default): passwd-file(zwelabantu,10.29.128.164): unknown user
dovecot: Jun 19 14:39:14 Info: pop3-login: Aborted login: user=<zwelabantu>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 14:49:14 Info: auth(default): passwd-file(root,10.29.128.164): unknown user
dovecot: Jun 19 14:49:16 Info: pop3-login: Aborted login: user=<root>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 14:49:16 Info: auth(default): passwd-file(zwelabantu,10.29.128.164): unknown user
dovecot: Jun 19 14:49:18 Info: pop3-login: Aborted login: user=<zwelabantu>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 14:59:18 Info: auth(default): passwd-file(root,10.29.128.164): unknown user
dovecot: Jun 19 14:59:18 Info: pop3-login: Aborted login: user=<root>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 14:59:18 Info: auth(default): passwd-file(zwelabantu,10.29.128.164): unknown user
dovecot: Jun 19 14:59:20 Info: pop3-login: Aborted login: user=<zwelabantu>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 15:09:20 Info: auth(default): passwd-file(root,10.29.128.164): unknown user
dovecot: Jun 19 15:09:22 Info: pop3-login: Aborted login: user=<root>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dovecot: Jun 19 15:09:22 Info: auth(default): passwd-file(zwelabantu,10.29.128.164): unknown user
dovecot: Jun 19 15:09:24 Info: pop3-login: Aborted login: user=<zwelabantu>, method=PLAIN, rip=10.29.128.164, lip=10.29.128.164, secured
dcmailserver:/var/log # tail -20 dovecot.log

I have now been struggling with this for 2 months, anyone who can help me with this will be much appreciated.

 

I dont have any ISPconfig installed. Am I suppose to one and if so please tell me how does it help my mail delivery.