==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.7 MYSQL edition.
# Get professional support from iRedMail Team: http://www.iredmail.org/support.html

- Linux/BSD distribution name and version:
root@ip-172-31-30-155:/etc# lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 16.04.3 LTS
Release:    16.04
Codename:    xenial

- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Sending internal mail works fine, tried sending mails to external domiains and get connection issues:

Dec 13 16:15:07 ip-172-31-30-155 postfix/submission/smtpd[2081]: disconnect from localhost[127.0.0.1] ehlo=2 starttls=1 auth=1 mail=1 rcpt=1 data=1 quit=1 commands=8
Dec 13 16:15:37 ip-172-31-30-155 postfix/smtp[2117]: connect to gmail-smtp-in.l.google.com[74.125.133.26]:25: Connection timed out
Dec 13 16:15:37 ip-172-31-30-155 postfix/smtp[2117]: connect to gmail-smtp-in.l.google.com[2a00:1450:400c:c02::1b]:25: Network is unreachable
Dec 13 16:16:07 ip-172-31-30-155 postfix/smtp[2117]: connect to alt1.gmail-smtp-in.l.google.com[209.85.233.26]:25: Connection timed out
Dec 13 16:16:07 ip-172-31-30-155 postfix/smtp[2117]: connect to alt1.gmail-smtp-in.l.google.com[2a00:1450:4010:c03::1a]:25: Network is unreachable
Dec 13 16:16:07 ip-172-31-30-155 postfix/smtp[2117]: connect to alt2.gmail-smtp-in.l.google.com[2404:6800:4003:c02::1b]:25: Network is unreachable

I must have done something wrong but I cannot for the life of me think what...