Net::SMTPAuthenticationError - email

Question

I'm trying to set up my rails 4 app so it sends email. Does anyone know why I am getting:
Net::SMTPAuthenticationError
534-5.7.9 Application-specific password required.
??????
I am using devise and have just set up a separate "share" mailer to send email. I've tried going to accounts.google.com/b/0/DisplayUnlockCaptcha as suggested in other responses to questions like this but nothing is changing when I restart the server and try to send an email as a user.
any ideas? Cheers!
config/environments/development.rb:
Rails.application.configure do
# Settings specified here will take precedence over those in config/application.rb.
# In the development environment your application's code is reloaded on
# every request. This slows down response time but is perfect for development
# since you don't have to restart the web server when you make code changes.
config.cache_classes = false
# Do not eager load code on boot.
config.eager_load = false
# Show full error reports and disable caching.
config.consider_all_requests_local = true
config.action_controller.perform_caching = false
# Don't care if the mailer can't send.
# config.action_mailer.raise_delivery_errors = true
config.action_mailer.delivery_method = :smtp
# Gmail SMTP server setup
ActionMailer::Base.smtp_settings = {
:address => "smtp.gmail.com",
:domain => "mail.google.com",
:port => 587,
:authentication => :plain,
:user_name => "myrealaddress#gmail.com",
:password => "myrealpassword",
:enable_starttls_auto => true
}
# Print deprecation notices to the Rails logger.
config.active_support.deprecation = :log
# Raise an error on page load if there are pending migrations.
config.active_record.migration_error = :page_load
# Debug mode disables concatenation and preprocessing of assets.
# This option may cause significant delays in view rendering with a large
# number of complex assets.
config.assets.debug = true
# Adds additional error checking when serving assets at runtime.
# Checks for improperly declared sprockets dependencies.
# Raises helpful error messages.
config.assets.raise_runtime_errors = true
# Raises error for missing translations
# config.action_view.raise_on_missing_translations = true
config.action_mailer.default_url_options = { :host => 'localhost:3000' }
# false prevents mail from being sent in development environment
config.action_mailer.perform_deliveries = true
end
mailer/share:
class Share < ActionMailer::Base
default_url_options[:host] = "localhost:3000"
default from: "myrealaddress#gmail.com"
def profile(profile, destination)
#profile = profile
mail(to: destination, subject: "sent you stuff")
end
end

Answer 1

The error is because two-factor authentication is enabled for your account. All you need to do to use a gmail account with two-factor authentication enabled is generate a new app password to use with your mailer configuration.
A new app password for gmail can be generated here - https://security.google.com/settings/security/apppasswords.
When generating a new password choose Mail for the Select App setting and Other(Custom name) for the Select Device setting.
Once you have the new password update your mailer configuration with the random string that Google generates for you and you should be set.