```ruby
# frozen_string_literal: true

class ApplicationMailer < ActionMailer::Base
  default from: "dashboard@#{ENV['dashboard_url']}"
  layout 'mailer'
  add_template_helper(SurveysUrlHelper)
end
```

Set a default reply-to address
user
```ruby
# frozen_string_literal: true

class ApplicationMailer < ActionMailer::Base
  default from: "dashboard@#{ENV['dashboard_url']}",
          reply_to: ENV['default_reply_email']
  layout 'mailer'
  add_template_helper(SurveysUrlHelper)
end
```
assistant