We have not been able to successfully get the iRedpro working. We used iRedmail Eassy to install and provide the pro license key. The mails are getting blocked due to it trying to send on port 25. My understanding was that by default this would be 587 and not port 25.  Softlayer does not allow port 25 and we do not want to open it either.

How to configure the default to be port 587 only for sending email and NOT to port 25. All files say do not edit, managed by ansible .
Here are the lines from mail.log that indicate the connection going out to gmail at port 25.

Jun  7 05:20:48 sopa-mail postfix/smtp[5143]: connect to gmail-smtp-in.l.google.com[172.217.195.27]:25: Connection timed out
Jun  7 05:20:48 sopa-mail postfix/smtp[5143]: connect to gmail-smtp-in.l.google.com[2607:f8b0:4003:c01::1a]:25: Network is unreachable
Jun  7 05:20:48 sopa-mail postfix/smtp[5143]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:4002:c05::1b]:25: Network is unreachable
Jun  7 05:21:18 sopa-mail postfix/smtp[5143]: connect to alt1.gmail-smtp-in.l.google.com[64.233.176.26]:25: Connection timed out
Jun  7 05:21:48 sopa-mail postfix/smtp[5143]: connect to alt2.gmail-smtp-in.l.google.com[209.85.144.26]:25: Connection timed out
Jun  7 05:21:48 sopa-mail postfix/smtp[5143]: 45KrSy439Cz1yhv: to=<angad108chauhan@gmail.com>, relay=none, delay=90, delays=0.01/0.03/90/0, dsn=4.4.1,
status=deferred (connect to alt2.gmail-smtp-in.l.google.com[209.85.144.26]:25: Connection timed out)
Jun  7 05:26:46 sopa-mail postfix/smtp[5594]: connect to gmail-smtp-in.l.google.com[2607:f8b0:4003:c01::1b]:25: Network is unreachable
Jun  7 05:27:16 sopa-mail postfix/smtp[5594]: connect to gmail-smtp-in.l.google.com[172.217.195.26]:25: Connection timed out
Jun  7 05:27:16 sopa-mail postfix/smtp[5594]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:4002:c05::1a]:25: Network is unreachable
Jun  7 05:27:46 sopa-mail postfix/smtp[5594]: connect to alt1.gmail-smtp-in.l.google.com[64.233.176.26]:25: Connection timed out
Jun  7 05:27:46 sopa-mail postfix/smtp[5594]: connect to alt2.gmail-smtp-in.l.google.com[2607:f8b0:400d:c0e::1b]:25: Network is unreachable
Jun  7 05:27:46 sopa-mail postfix/smtp[5594]: 45KrMx6sj1z1ySn: to=<angad108chauhan@gmail.com>, relay=none, delay=709, delays=649/0.02/60/0, dsn=4.4.1,
status=deferred (connect to alt2.gmail-smtp-in.l.google.com[2607:f8b0:400d:c0e::1b]:25: Network is unreachable)
Jun  7 05:31:46 sopa-mail postfix/smtp[5925]: connect to gmail-smtp-in.l.google.com[2607:f8b0:4003:c01::1a]:25: Network is unreachable
Jun  7 05:32:16 sopa-mail postfix/smtp[5925]: connect to gmail-smtp-in.l.google.com[172.217.195.26]:25: Connection timed out
Jun  7 05:32:16 sopa-mail postfix/smtp[5925]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:4002:c05::1b]:25: Network is unreachable
Jun  7 05:32:46 sopa-mail postfix/smtp[5925]: connect to alt1.gmail-smtp-in.l.google.com[64.233.176.26]:25: Connection timed out
Jun  7 05:32:46 sopa-mail postfix/smtp[5925]: connect to alt2.gmail-smtp-in.l.google.com[2607:f8b0:400d:c0e::1a]:25: Network is unreachable
Jun  7 05:32:46 sopa-mail postfix/smtp[5925]: 45KrSy439Cz1yhv: to=<angad108chauhan@gmail.com>, relay=none, delay=748, delays=688/0.02/60/0, dsn=4.4.1,
status=deferred (connect to alt2.gmail-smtp-in.l.google.com[2607:f8b0:400d:c0e::1a]:25: Network is unreachable)
Jun  7 05:41:46 sopa-mail postfix/smtp[6465]: connect to gmail-smtp-in.l.google.com[2607:f8b0:4003:c01::1b]:25: Network is unreachable
==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):
- Deployed with iRedMail Easy or the downloadable installer?
- Linux/BSD distribution name and version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====
version .  2019060601 (Backend: mariadb, Date: 2019-06-06 14:32:03) iRedMail Easy: https://www.iredmail.org/easy.html
installed using iredmail easy. Have a pro license.
Ubuntu 18.04.2 LTS ,  bionic
MySQL (Mariadb)
Ngnix
Manage mail accounts with iRedAdmin-Pro :