/mail/ will tell you what's being mailed and why.

@chad
I've looked at /mail/ and i see all the queue are Mail related.
and it seems that the first mail is the verification mail to users "Mail 1 Content Redacted".
Is there anyway to terminate all these mail? I have kept the server on for more than 8 hours and the queue has not expire or terminate by itself yet.

I think I am having issue configuring the smtp at first, and this caused all the mails to be stuck in the queue. I can't test the mail until the queue started moving.
Below are some steps i have taken to configure the mail server. Maybe you can help me to see if I am missing any step.

1. I added the following at /config/group/metamta/
   • metamta.domain := ip address of the site
   • metamta.mail-adapter := PhabricatorMailImplementationPHPMailerAdapter
2. In my directory /phabricator/htdocs/conf/custom , i've created a file PhabricatorMail.conf.php with the following: (These are the same config i've used in mediawiki, without username & pwd)

<?php return array(   // Specify whichever keys and values you want to set.    $
  'phpmailer.smtp-host' => '172.10.10.10',
 'phpmailer.smtp-port' => 25,
 'phpmailer.smtp-protocol' => 'ssl',
);

1. Then i insert the following config file into the ENVIRONMENT by doing the following:

phabricator/ $ echo custom/PhabricatorMail.conf.php  > conf/local/ENVIRONMENT
phabricator/ $ cat conf/local/ENVIRONMENT
custom/PhabricatorMail.conf.php 

1. 1. I restarted the server.
2. The mails are still sitting in the queue not sent out.

Very much appreciated for the help.

In my directory /phabricator/htdocs/conf/custom

Did our documentation somewhere tell you to do this? We shouldn't be. It's all in the Config application.

/config/group/phpmailer/ is where to set the values for PHPMailer

In the /config/group/phpmailer/ they are shown as locked.
Configuration Locked
This configuration is locked and can not be edited from the web interface. Use ./bin/config in phabricator/ to edit it.

How do i edit a locked parameter?

Use ./bin/config in phabricator/ to edit it.

@chad,
I have configure the following:
sudo ./bin/config set phpmailer.smtp-host 172.10.10.10
sudo ./bin/config set phpmailer.smtp-port 25
sudo ./bin/config set phpmailer.smtp-protocol ssl

And also the following in /config/group/metamta
metamta.domain = "phabricator.example.com"
metamta.mail-adapter = "PhabricatorMailImplementationPHPMailerAdapter"

and the mail system still does not work. It still queues. I'm wondering where do i set IDHost and also auth? In my MW i have auth set to false. In phab not sure where is that settings.

I'm wondering for example in my mediawiki i have the following:
$wgSMTP = array(
'host' => "172.10.10.10",
'IDHost' => "toyo.com",
'port' => 25,
'auth' => false,
'username' => "",
'password' => ""
);