diff --git a/core/lib/spree/mailer_previews/carton_preview.rb b/core/lib/spree/mailer_previews/carton_preview.rb
index 41c09f75477..a1c4653a263 100644
--- a/core/lib/spree/mailer_previews/carton_preview.rb
+++ b/core/lib/spree/mailer_previews/carton_preview.rb
@@ -5,7 +5,8 @@ class MailerPreviews
     class CartonPreview < ActionMailer::Preview
       def shipped
         carton = Carton.joins(:orders).last
-        raise "Your database needs at one shipped order with a carton to render this preview" unless carton
+        raise "Your database needs at least one shipped order with a carton to render this preview" unless carton
+
         Spree::Config.carton_shipped_email_class.shipped_email(order: carton.orders.first, carton: carton)
       end
     end