Swiftmailer times out when trying to send an email from my Symfony App (Flex)

Hello peeps!

I have a Symfony Flex (v4) app on one of my droplets. I am using SwiftMailer in my app so i can send emails. It sends to another host (a mail server) the email so it can handles it.

The MAILER_URL is in an Apache2 SetEnv variable and it something like this:

SetEnv MAILER_URL "smtp://amazing.domain.org:25?etcetcetc"

The log of my applications says that it timed out

[2018-03-17 21:24:36] app.ERROR: Exception occurred while flushing email queue: Connection could not be established with host amazing.domain.org [Connection timed out #110] [] []

• In my dev environment it sends the email correctly.
• Its not a problem of the email service provider… I’ve checked it and its working great
• The settings of the connection are correct… so its not a wrong password nor username nor type of connection nor port of the host…

I am starting to believe that something is blocking it… maybe i need to add some outbound rule… any ideas? Any rule i have to add to my firewall? to my ufw Ubuntu droplet?

Thanks for the help in advance. I love this community. Much love.