Heroku code example unable to activate maintenance mode

The option of “Full SSL (strict)” is not viable as CF anticipates receiving a certificate from Heroku and displays an error page. However, one can opt for “Full SSL” which establishes an HTTPS connection between Heroku and CF, but without CF’s certificate validation process.

Solution 1:

/usr/sbin/sendmail: not found

It indicates that the


package is missing from your Linux installation.

Assuming you are using a VPS, it would be advisable to install the


package through the

sudo apt-get install sendmail

method. Nonetheless, since you are using Heroku, it is uncertain whether this is the root cause of the problem.


Based on the absence of any additional errors, I suggest taking the following steps.

  1. Replace the SMTP service with a third-party provider, such as Sendgrid or Mandrill.
  2. Experiment with refraining from sending the email to determine if it improves the signup process.
  3. check if the user exists in the database.

Beginning with


, it’s worth noting that the user appears to be in the process of being generated but there may be an issue with sending them. While the logs are inconclusive, it would be helpful to confirm whether the user objects have been successfully created.

$ heroku run rails c
$ user = User.last
 [user credentials displayed]

With this feature, you can view the latest addition to the


database. In case it matches your submission, it will reinforce my belief that the email mechanism is malfunctioning.

After that, it’s important to verify that your email configuration is accurate. To accomplish this, you may want to consider utilizing some helpful extensions, with Mandrill being a highly recommended option.

config.action_mailer.smtp_settings = {
        :address   => "smtp.mandrillapp.com",
        :port      => 25, # ports 587 and 2525 are also supported with STARTTLS
        :enable_starttls_auto => true, # detects and uses STARTTLS
        :user_name => ENV["MANDRILL_USERNAME"],
        :password  => ENV["MANDRILL_PASSWORD"], # SMTP password is any valid API key
        :authentication => 'login', # Mandrill supports 'plain' or 'login'
        :domain => 'yourdomain.com', # your domain to identify your server when connecting

Delete the configuration for both





It appears that the root of your problems is centered around the act of sending an email.

It seems like an email confirming something, and you can turn it off using Devise. Although I have no experience with this, I have provided a resource for you.

user = User.new

Solution 2:

I would like to express my gratitude to @Rich Peck and @Mandeep for their hard work. After conducting more thorough research, I was able to resolve the problem by simply adding one line of code.

config.action_mailer.smtp_settings = {
      address: 'smtp.gmail.com',
      port: 587,
      domain: 'gmail.com',
      user_name: '[email protected]',
      password: 'mygmail_password',
      authentication: 'plain',
      enable_starttls_auto: true,
      :openssl_verify_mode => 'none'  # This line added and it works fine

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