Net::SMTPAuthenticationError in UsersController#create - ruby-on-rails

Question

our Rails 3.2 application's "resend activation code" mail feature was working until the code was transferred from the previous developer to us. Now we get this error
Net::SMTPAuthenticationError in UsersController#create
Our mail settings remain untouched like this:
ActionMailer::Base.smtp_settings = {
:address => "smtp.sendgrid.net",
:port => 587,
:domain => "example.com",
:user_name => "username",
:password => "password",
:authentication => "plain",
:enable_starttls_auto => true
}
We are somehow not able to figure it out as to why the email stop's working.
We have checked the gmail server also responding back to us via telnet.
We have also enabled the Less Secure Apps feature of Gmail's in Security -> Account permissions -> Access for less secure apps
Thanks in advance.

Answer 1

You mentioned using Gmail's settings, I'd say you should try this:
ActionMailer::Base.smtp_settings = {
address: "smtp.gmail.com",
port: 587,
user_name: ENV['GMAIL_USERNAME'],
password: ENV['GMAIL_PASSWORD'],
authentication: :plain,
enable_starttls_auto: true
}
If you're using Sendgrid, as above you should have something like:
ActionMailer::Base.smtp_settings = {
user_name: ENV['SENDGRID_USERNAME'],
password: ENV['SENDGRID_PASSWORD'],
domain: 'heroku.com', #for your helo domain
address: 'smtp.sendgrid.net',
port: 587,
authentication: :plain,
enable_starttls_auto: true
}
Don't forget to define your ENV variables appropriately.
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