I am running Ubuntu and I am trying to setup my mail server using ISPConfig 3. Here is the error I am getting:

Mail Queue (Server : droplet.domain.co.za)
Data from: 2014-07-16 12:40
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
0D0FA25451 627 Wed Jul 16 03:21:02 root@droplet.domain.co.za
(connect to 127.0.0.1[127.0.0.1]:10024: Connection refused)
archie@domain.co.za

AC0AF23289 628 Wed Jul 16 12:19:01 root@droplet.domain.co.za
(mail transport unavailable)
moshidi@domain.co.za

AE3462545B 679 Wed Jul 16 06:55:19 root@droplet.domain.co.za
(mail transport unavailable)
root@droplet.domain.co.za

50C5425443 679 Wed Jul 16 01:24:04 amavis@droplet.domain.co.za
(connect to 127.0.0.1[127.0.0.1]:10024: Connection refused)
amavis@droplet.domain.co.za

-- 3 Kbytes in 4 Requests.

NB: domain (my domain is not domain)

Whenever I sent emails to the created mailboxes, they do not come through. An error from my gmail account is as followS:

Technical details of temporary failure:
The recipient server did not accept our requests to connect. Learn more at http://support.google.com/mail/bin/answer.py?answer=7720
[(0) domain.co.za. [192.xxx.xxx.xx]:25: Connection dropped]