Rails 4 Sendgrid integration giving error - Unauthenticated senders not allowed

Question

I have integrated Sendgrid settings on a Rails 4 server. These settings work fine for development environment. But this is giving error on production environment.

Net::SMTPFatalError (550 Cannot receive from specified address <[email protected]>: Unauthenticated senders not allowed)

config/initializers/email_setup.rb

ActionMailer::Base.smtp_settings = {
   :address              => "smtp.sendgrid.net",
   :domain               => DOMAIN,
   :user_name            => ENV['SENDGRID_USERNAME'],
   :password             => ENV['SENDGRID_PASSWORD'],
   :authentication       => "plain",
   :enable_starttls_auto => true
}

config/initializers/devise.rb

config.mailer_sender = '[email protected]'

config/environments/production.rb

# Default URL
config.action_mailer.default_url_options = { host: 'mysite.mydomain.com' }

DOMAIN = 'mysite.mydomain.com'

Answer 1

According to sendgrid support team, this error comes when username or password are incorrect. I tried logging manually into the smtp server through telnet and it was working.

On my server commandline, I followed these steps:

telnet smtp.sendgrid.net 587
EHLO
AUTH LOGIN
Enter username in Base64
Enter password in Base64

Link to convert text into Base64 - http://www.opinionatedgeek.com/dotnet/tools/base64encode/

The ENV variables were somehow not working on my production environment. As a workaround, I tried adding the username and password directly and it worked.

Answer 2

I have also faced the same problem and fixed it by adding the following:

config/environment.rb

ActionMailer::Base.smtp_settings = {
  :address              => "smtp.sendgrid.net",
  :domain               => DOMAIN,
  :user_name            => ENV['SENDGRID_USERNAME'],
  :password             => ENV['SENDGRID_PASSWORD'],
  :authentication       => "plain",
  :enable_starttls_auto => true
}
ActionMailer::Base.default_url_options = { host: 'mysite.mydomain.com' }

config/application.rb

ActionMailer::Base.delivery_method = :smtp

The letter_opener gem is very useful if you want to test sending emails in development mode. If you want to overwrite the letter_opener, add the following configuration

config/environments/development.rb

ActionMailer::Base.delivery_method= :letter_opener

And also add the port under ActionMailer::Base.smtp_settings.

Answer 3

You are probably loading your environment variables after you are trying to initialize your mailer. You can do the initialization directly after loading your variables to be sure that they exist.

Set up a config file with your username and password variables:

# config/mailer.yml
production:
   SENDGRID_USERNAME: 'username'
   SENDGRID_PASSWORD: 'password'

Set up an initializer file:

# config/initializers/mailer.rb
if Rails.env.production?
  config_path = File.expand_path(Rails.root.to_s + '/config/mailer.yml')
  if File.exists? config_path
    ENV.update YAML.load_file(config_path)[Rails.env]
  end

  ActionMailer::Base.smtp_settings = {
    :address        => 'smtp.sendgrid.net',
    :port           => '587',
    :authentication => :plain,
    :user_name      => ENV["SENDGRID_USERNAME"],
    :password       => ENV["SENDGRID_PASSWORD"],
    :domain         => "yourdomain",
  }
end