Getting 500 Internal Server Error while trying to send an email using Mailgun in Heroku , using Rail-CodePudding

I was following this tutorial right here

Some additional things that I've noticed is that error seems to stem from whet the @contact.deliver action is done, I've tried making my own simple mailer in place of using mail_form, and using .deliver_now triggers the same error, using deliver_later does not, but the mail never gets sent, so I suspect the error comes from elsewhere.

Any help would be greatly appreciated, as I've reached an impasse regarding this situation

CodePudding user response：

Thanks to the help of the comments, I was able to notice by the line in the heroku logs:

2022-04-28T20:35:32.116916 00:00 app[web.1]: [b1e694c5-cea3-427f-bbdd-aa3cc3a92d6b] Errno::ECONNREFUSED (Connection refused - connect(2) for 127.0.0.1:25):

The port being used was 25 instead of 587 meaning that the block

ActionMailer::Base.smtp_settings = {
  :port           => ENV['MAILGUN_SMTP_PORT'],
  :address        => ENV['MAILGUN_SMTP_SERVER'],
  :user_name      => ENV['MAILGUN_SMTP_LOGIN'],
  :password       => ENV['MAILGUN_SMTP_PASSWORD'],
  :domain         => 'https://www.example.com/',
  :authentication => :plain,
}

Was being ignored, by instead encompassing those option inside a config.action_mailer.smtp_settings I was able to resolve the issue.