带有SMTP的Rails Action Mailer ArgumentError

Question

I am trying to send an email to multiple recipients:

class SubscriberMailer < ApplicationMailer
  default from: "email@gmail.com"
  default to: Subscriber.all.map { |sub| sub.email }

  def newsletter(subscriber)
    @subscriber = subscriber
    mail subject: "New newsletter"
  end
end

in NewslettersController:

def send(newsletter)
  @subscribers = Subscriber.all
  SubscriberMailer.newsletter(@subscribers).deliver
end

I am getting an error:

ArgumentError in NewslettersController#index
An SMTP To address is required to send a message. Set the message smtp_envelope_to, to, cc, or bcc address.

Thanks for help!

Answer 1

Change your default to: :

class SubscriberMailer < ApplicationMailer
  default from: "email@gmail.com"
  default to: Subscriber.pluck(:email).join(', ')

  # some code here
end

Answer 2

It isn't about SMTP

Something in your Subscriber.all.map { |sub| sub.email } Subscriber.all.map { |sub| sub.email } is not working. Do you use a real, working address? If not, try with one.

And if all emails are real ones, then you may try something like

default to: Subscriber.all.collect(&:email).join(",")

Hope it helps!