Net::OpenTimeout: execution expired while testing the SMTP and when trying to send an activation url

Summary

Steps to reproduce

install gitlab, configure SMTP using extisting config in /etc/gitlab/gitlab.rb

Example Project

My config:

###! **Use smtp instead of sendmail/postfix.**

 gitlab_rails['smtp_enable'] = true
 gitlab_rails['smtp_address'] = "mail.<domain>"
 gitlab_rails['smtp_port'] = 25
 gitlab_rails['smtp_user_name'] = "git@<domain>"
 gitlab_rails['smtp_password'] = "<password>"
 gitlab_rails['smtp_domain'] = "mail.<domain>"
 gitlab_rails['smtp_authentication'] = "login"
 gitlab_rails['smtp_enable_starttls_auto'] = false
 gitlab_rails['smtp_tls'] = false
 gitlab_rails['smtp_force_ssl'] = false
 gitlab_rails['smtp_tls'] = false;
 gitlab_rails['smtp_openssl_verify_mode'] = 'none'

###! **Can be: 'none', 'peer', 'client_once', 'fail_if_no_peer_cert'**
###! Docs: http://api.rubyonrails.org/classes/ActionMailer/Base.html
 gitlab_rails['smtp_openssl_verify_mode'] = 'peer'

I have tried both TLS and no encryption, both fail

What is the current bug behavior?

SMTP fails with Net::OpenTimeout: execution expired

What is the expected correct behavior?

Mail sent correctly

Relevant logs and/or screenshots

irb(main):001:0> Notify.test_email('destination_email@address.com', 'Message Subject', 'Message Body').deliver_now

Notify#test_email: processed outbound mail in 482.1ms
^[[D^H
Sent mail to destination_email@address.com (30044.1ms)
Date: Sun, 17 Jun 2018 08:06:25 +0000
From: GitLab <gitlab@git.b<domain>>
Reply-To: GitLab <noreply@<domain>>
To: destination_email@address.com
Message-ID: <5b261681af6ae_3a4e3ff196edb0d033dd@<domain>>
Subject: Message Subject
Mime-Version: 1.0
Content-Type: text/html;
 charset=UTF-8
Content-Transfer-Encoding: 7bit
Auto-Submitted: auto-generated
X-Auto-Response-Suppress: All

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html><body><p>Message Body</p></body></html>

Net::OpenTimeout: execution expired
	from /opt/gitlab/embedded/lib/ruby/2.3.0/net/smtp.rb:542:in `initialize'
	from /opt/gitlab/embedded/lib/ruby/2.3.0/net/smtp.rb:542:in `open'
	from /opt/gitlab/embedded/lib/ruby/2.3.0/net/smtp.rb:542:in `tcp_socket'
	from /opt/gitlab/embedded/lib/ruby/2.3.0/net/smtp.rb:552:in `block in do_start'
	from /opt/gitlab/embedded/lib/ruby/2.3.0/timeout.rb:101:in `timeout'
	from /opt/gitlab/embedded/lib/ruby/2.3.0/net/smtp.rb:551:in `do_start'
	from /opt/gitlab/embedded/lib/ruby/2.3.0/net/smtp.rb:521:in `start'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/mail-2.7.0/lib/mail/network/delivery_methods/smtp.rb:109:in `start_smtp_session'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/mail-2.7.0/lib/mail/network/delivery_methods/smtp.rb:100:in `deliver!'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/mail-2.7.0/lib/mail/message.rb:2160:in `do_delivery'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/mail-2.7.0/lib/mail/message.rb:260:in `block in deliver'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionmailer-4.2.10/lib/action_mailer/base.rb:543:in `block in deliver_mail'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activesupport-4.2.10/lib/active_support/notifications.rb:164:in `block in instrument'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activesupport-4.2.10/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/activesupport-4.2.10/lib/active_support/notifications.rb:164:in `instrument'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionmailer-4.2.10/lib/action_mailer/base.rb:541:in `deliver_mail'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/mail-2.7.0/lib/mail/message.rb:260:in `deliver'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/actionmailer-4.2.10/lib/action_mailer/message_delivery.rb:85:in `deliver_now'
	from (irb):1
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/railties-4.2.10/lib/rails/commands/console.rb:110:in `start'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/railties-4.2.10/lib/rails/commands/console.rb:9:in `start'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/railties-4.2.10/lib/rails/commands/commands_tasks.rb:68:in `console'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/railties-4.2.10/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
	from /opt/gitlab/embedded/lib/ruby/gems/2.3.0/gems/railties-4.2.10/lib/rails/commands.rb:17:in `<top (required)>'
	from bin/rails:14:in `require'
	from bin/rails:14:in `<main>'
irb(main):002:0> exit

Also i have tested if the server can reach the SMTP server:

Starting Nmap 7.01 ( https://nmap.org ) at 2018-06-17 08:24 UTC
Nmap scan report for <domain> (<IPv4>)
Host is up (0.00076s latency).
rDNS record for <IPv4>: mail.<domain>
PORT   STATE SERVICE
25/tcp open  smtp

Results of GitLab environment info

Expand for output related to GitLab environment info

System information System: Ubuntu 16.04 Current User: git Using RVM: no Ruby Version: 2.3.7p456 Gem Version: 2.6.14 Bundler Version:1.13.7 Rake Version: 12.3.1 Redis Version: 3.2.11 Git Version: 2.16.4 Sidekiq Version:5.0.5 Go Version: unknown

GitLab information Version: 10.8.4 Revision: 2268d0c Directory: /opt/gitlab/embedded/service/gitlab-rails DB Adapter: postgresql URL: http://git. HTTP Clone URL: http://git./some-group/some-project.git SSH Clone URL: git@git.:some-group/some-project.git Using LDAP: no Using Omniauth: no

GitLab Shell Version: 7.1.2 Repository storage paths:

default: /var/opt/gitlab/git-data/repositories Hooks: /opt/gitlab/embedded/service/gitlab-shell/hooks Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:

`sudo gitlab-rake gitlab:check SANITIZE=true`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true`)

(we will only investigate if the tests are passing)
``Checking GitLab Shell ...

GitLab Shell version >= 7.1.2 ? ... OK (7.1.2)
Repo base directory exists?
default... yes
Repo storage directories are symlinks?
default... no
Repo paths owned by git:root, or git:git?
default... yes
Repo paths access is drwxrws---?
default... yes
hooks directories in repos are links: ... 
1/2 ... ok
1/3 ... ok
1/5 ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK

Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful

Checking GitLab Shell ... Finished

Checking Sidekiq ...

Running? ... yes
Number of Sidekiq processes ... 1

Checking Sidekiq ... Finished

Reply by email is disabled in config/gitlab.yml
Checking LDAP ...

LDAP is disabled in config/gitlab.yml

Checking LDAP ... Finished

Checking GitLab ...

Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... skipped (no tmp uploads folder yet)
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ... 
1/2 ... yes
1/3 ... yes
1/5 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.5 ? ... yes (2.3.7)
Git version >= 2.9.5 ? ... yes (2.16.4)
Git user has default SSH configuration? ... yes
Active users: ... 1

Checking GitLab ... Finished
`

</pre>
</details>

### Possible fixes

I have tried everything i have found on web, but nothing worked.

Edited Jun 17, 2018 by Bumba laga