I know that this issue of getting delivery errors has been a hurdle on your part, POU27 & DanSH.

Let me share some information that our engineers identified the issue that QuickBooks IP addresses are being blocked by the public spam blocklist called Spamcop. With that being said, they're implementing measures to fix this.

You may consider using other ways of sending invoices to your customers. These are the following:

• You can save the invoice as a PDF and send it via email through your business or other email address.
• You can send your customer a link to their invoice via SMS or messenger service. Just click on "save and share link" then select "copy link" and paste it into your SMS or messenger.
• You can save your invoice as a PDF, print it, and send your customer their invoice via email.

We will send you an update as soon as this gets fixed.

Your understanding is much appreciated.