Connect with and learn from others in the QuickBooks Community.
Hello there, usercharlie.
Are you getting the Delivery Server Down error when emailing a sales transaction such as invoice? This error is usually related to the attachments or the way your Company email information is set up.
There are different ways to correct this. You can visit this article to see the detailed guide on how to remove the error: Delivery Errors when trying to email a sales form.
After that, you can attempt to send again the transaction.
Let us know how this goes so we can further assist you. Have a great day!