Rails 4 Sendgrid integration giving error - Unauthenticated senders not allowed - ruby-on-rails-4

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 <simmi#mydomain.com>: 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 = 'simmi#mydomain.com'
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

Answer 4

If your production environment is Heroku:
Login to your Heroku account and select the application. Under "Settings", click the "Reveal Config Vars" button. Enter in your sendgrid key and value pairs, then submit. Run: heroku restart.