i18nize the global error message

app/controllers/split_checkout_controller.rb

@@ -45,7 +45,7 @@ class SplitCheckoutController < ::BaseController
       if @shipping_method_id.blank?
         @order.errors.add(:base, "no_shipping_method_selected")
       end
-      flash.now[:error] = "Saving failed, please update the highlighted fields: #{@order.errors.full_messages}"
+      flash.now[:error] = "#{I18n.t('split_checkout.errors.global')}"
       render :edit
     end
   end

config/locales/en.yml

@@ -1692,6 +1692,7 @@ en:
       submit: Complete order
       cancel: Back to Payment method
     errors:
+      global: "Saving failed, please update the highlighted fields."
       required: Field cannot be blank
       invalid_number: "Please enter a valid phone number"
       invalid_email: "Please enter a valid email address"