ActionMailer with SMTP - Bad recipient address syntax

Question

My user has email with this format: "[email protected]". Mailgun validation succeeded but Rails couldn't send email to the address. I'm using SMTP with Mandrill. This is the error message:

/home/johnny/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/net/smtp.rb:948:in `check_response': 401 4.1.3 Bad recipient address syntax (Net::SMTPServerBusy)

Do you have any idea?

Thanks in advance.

Updated:

This sample code (with valid SMTP configuration) would raise the error:

#!/usr/bin/env ruby
require 'mail'

options = {
    address:      "smtp.mandrillapp.com",
    port:     587,
    domain:     "mydomain.com",
    authentication:   "login",
    user_name:    "[email protected]",
    password:     "mypassword",
    enable_starttls_auto: false
}

Mail.defaults do
    delivery_method :smtp, options
end

Mail.deliver do
    from '[email protected]'
    to "[email protected]"
    subject 'Testing sendmail'
    body 'Testing sendmail'
end

Answer 1

Even if the starting dash in the email address is valid, most mail servers do not accept such emails due to restrictions for command line arguments.

A quick fix you can try is wrapping the email address with angle brackets:

Mail.deliver do
  from '[email protected]'
  to "<[email protected]>"
  subject 'Testing sendmail'
  body 'Testing sendmail'
end