Styjun

I'm currently working on an application with a mailer system. It was working fine, sending a welcome email and sending instructions to reset password, but now and only when I try to send reset instructions I have this error.

ArgumentError (SMTP From address may not be blank: nil):

I'm using a custom domain like so noreply@mycustomdomain.com
And here is my configuration

development.rb

 config.action_mailer.raise_delivery_errors = true
 config.action_mailer.perform_caching = false
 config.action_mailer.default_url_options = host: 'localhost:3000' 

 config.action_mailer.delivery_method = :smtp
 config.action_mailer.smtp_settings = 
 address: 'smtp.gmail.com',
 port: '587',
 domain: 'gmail.com',
 authentication: :plain,
 enable_starttls_auto: true,
 user_name: Rails.application.secrets.mailer_username,
 password: Rails.application.secrets.mailer_password

Any idea ?

Edit

class UserMailer < ApplicationMailer
 default from: 'noreply@mycustomdomain.com'

 def welcome_email(user)
 @user = user
 @url = 'http://localhost:3000/users/sign_in'
 mail(to: @user.email, subject: 'Bienvenue')
 end

 def generate_new_password_email
 user = User.find(params[:user_id])
 user.send_reset_password_instructions
 end

 def reset_password; end
end

I had the same problem, and the reason behind that was i working in development but my mailer was searching the smtp_settings in the production, so to solve the issue you can change the mailer settings or you can copy the same smtp_settings into production.

In devise.rb config.mailer_sender = 'please-change-me-at-config-initializers-devise@example.com' had been commented.
Config.mailer_sender was never initialized and so always nil even if I set it with default from:

It looks like you don't have a From header in your email. A good practice would be to put the following line into your ApplicationMailer:

class ApplicationMailer
 default from: 'noreply@mycustomdomain.com'

 # ...
end

To override this in your inheriting mailers, simply declare the same statement. To override it in individual mail methods, put it into the mail call like so:

def new_message(user, message)
 mail(
 to: user.email,
 subject: "New message from #message.sender.name",
 from: message.sender.email
 )
end

Hope that helps

You could try setting :from in your config, using the default_option like this,

config.action_mailer.default_options = from: 'noreply@mycustomdomain.com' 

I stumbled upon the same problem. My solution was, I edited config/initializers/devise.rb changed a line from config.mailer_sender = 'please-change-me-at-config-initializers-devise@example.com'
to config.mailer_sender = ENV["default_from_email"]