Description of problem:

For the default mail client, the test email will not be delivered if the Postfix service is not running on the Satellite server.

Doc link
 https://content-preview.docs.redhat.com/en/documentation/red_hat_satellite/6.16/html-single/administering_red_hat_satellite/index#Testing_Email_Delivery_admin

How reproducible:

 Always.

Is this issue a regression from an earlier version:

Steps to Reproduce:

1. In the Satellite web UI, navigate to Administer > Users.
2. Click on the username.
3. On the Email Preferences tab, click Test email.

In production.log      // As per the logs it's 200 OK

2024-09-09T10:49:29 [I|app|39301f46] Processing by UsersController#test_mail as */*
2024-09-09T10:49:29 [I|app|39301f46] Parameters:

{"user_email"=>"sadas@redhat.com", "id"=>"4-admin"}

2024-09-09T10:49:29 [I|app|39301f46] Rendered user_mailer/tester.html.erb within layouts/application_mailer (Duration: 42.6ms | Allocations: 703)
2024-09-09T10:49:30 [I|app|39301f46] Rendered layout layouts/application_mailer.html.erb (Duration: 89.2ms | Allocations: 1387)
2024-09-09T10:49:30 [I|app|39301f46] Rendered user_mailer/tester.text.erb (Duration: 24.2ms | Allocations: 180)
2024-09-09T10:49:30 [I|app|39301f46] Delivered mail 66de8562135b5_375c6f9c8-383@vm205-27.uatlab.pnq2.redhat.com.mail (189.7ms)
2024-09-09T10:49:30 [I|app|39301f46] Completed 200 OK in 364ms (Views: 0.2ms | ActiveRecord: 2.4ms | Allocations: 22043)

Actual behavior:

However it's stuck in the mailq.

1. mailq
   postqueue: warning: Mail system is down - accessing queue directly
   Queue ID {}Size{} --{}Arrival Time{}-- Sender/Recipient------
   24CC52C05E2F 1858 Mon Sep 9 10:49:30 satellite-noreply@uatlab.pnq2.redhat.com
   sadas@redhat.com

Expected behavior:

Documentation should include steps to enable and start the postfix service.

Business Impact / Additional info:

The documentation should highlight if the default mail client is used, the service should be enabled.

 # systemctl enable postfix

1. systemctl start postfix
   [root@vm205-27 ~]# mailq
   Mail queue is empty