Mail server not working with Postfix Dovecot

[Mariano Jara Melagrani]

I'm running Ubuntu Server 14.04.3

mariano at server1:~$ cat /etc/issue
Ubuntu 14.04.3 LTS \n \l

I want ro run my own mail server with my own domain, so I've installed
Postfix and Dovecot following this guide:

https://help.ubuntu.com/lts/serverguide/serverguide.pdf

I've configured Thunderbird to receive and send mails from my mail
server using my domain (mail.jaramelagrani.com.ar), but I'm not being
able to receive or send mails. I've sent test mails, using Thunderbird
and the web interface, from a Google and Hotmail accounts to my domain,
but I'm not receiving them. Later on I've received at those accounts
(Google and Hotmail) a Delivery Status Notification (Delay) message saying:

"This is an automatically generated Delivery Status Notification

THIS IS A WARNING MESSAGE ONLY.

YOU DO NOT NEED TO RESEND YOUR MESSAGE.

Delivery to the following recipient has been delayed:

     mariano at jaramelagrani.com.ar

Message will be retried for 2 more day(s)

Technical details of temporary failure:
The recipient server did not accept our requests to connect. Learn more
at https://support.google.com/mail/answer/7720
[(10) mail.jaramelagrani.com.ar. [181.230.43.12]:25: socket error]..."


I've checked the logs and looked the errors up on DDG but couldn't find
a solution.

I've got ports 25, 110, 465 and 995 open, facing the internet, so I
doubt this is a firewall issue. I don't know if my ISP is blocking those
ports. I've sent them a message asking about it, but I haven't got a
response yet.

I've posted the logs and Postfix config at

http://paste.ubuntu.com/13774193/

I'm clueless so any pointers or help would be much appreciated.

-- 
Atte.
Mariano Jara Melagrani
http://www.jaramelagrani.com.ar/

0x80319128 GnuPG v1.4 (GNU/Linux)
http://pgp.mit.edu/
http://keyserver.pgp.com/
http://keyserver.ubuntu.com:11371/