class NotifierMailer < ActionMailer::Base
  def send_mail(response_code)
    mail to: CONFIG.fetch(:notification_email),
         subject: 'Service Change Notifier has failed',
         body: "The service change notifier request failed
         with the following status code: #{response_code}."
  end
end

class NotifierMailer < ActionMailer::Base
  def send_mail(service, response_code)
    mail to: CONFIG.fetch(:notification_email),
         subject: 'Service Change Notifier has failed',
         body: "The service change notifier request failed
         with the service #{service} and status code #{response_code}."
  end
end

Update mailer method to mention problematic service
Update mailer method to mention problematic service
