rails I am a beginner.

I'm having trouble with Ruby on Rails Tutorial Chapter 11 11.4 "Mail Sending in Production".
The email from SendGrid will be delivered.

When connecting to the link from Activate in the email,

Cannot access this site .. The server IP address of .herokuapp.com was not found.
It is displayed like


  • Try it

The following article was used as a reference.

(host = '.herokuapp.com' has changed to your environment)


config.action_mailer.raise_delivery_errors = true
  config.action_mailer.delivery_method =: smtp
  host = '<your heroku app>.herokuapp.com'
  config.action_mailer.default_url_options = {host: host}
  ActionMailer :: Base.smtp_settings = {
    : address =>'smtp.sendgrid.net',
    : port =>'587',
    : authentication =>: plain,
    : user_name =>ENV ['SENDGRID_USERNAME'],
    : password =>ENV ['SENDGRID_PASSWORD'],
    : domain =>'heroku.com',
    : enable_starttls_auto =>true

$heroku config: get SENDGRID_USERNAME
$heroku config: get SENDGRID_PASSWORD
I applied the user_name password that was displayed in, but I fixed it because another error occurred.
* We referenced https://www.tutorialfor.com/go.php?id=74492 .


Hi<% = @ user.name%>,
Welcome to the Sample App! Click on the link below to activate your account:
<% = edit_account_activation_url (@ user.activation_token, email: @ user.email)%>

In the result of heroku logs,

Process exited with status 127
 Stopping all processes with SIGTERM
Process exited with status 143
There are three parts displayed in red with

. Is this related?
I'm in trouble without knowing what the error is.

  • Answer # 1

    It was a simple mistake.
    Healed after deleting.

  • Answer # 2

    Link from Activate in email

    This and


    Please tell me about this.

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