The issue is most likely an email delivery error, Dallas15. Various factors could explain why the invoices were not successfully sent via email.
On the other hand, the link between invoices and credit card payments should not cause delivery errors. PCI compliance focuses on securing payment card data, not affecting the email transmission of invoices without sensitive cardholder information.
After, verify that the invoices were sent successfully from our system. Resend them and ensure they are delivered to the correct recipients. Here's how:
- Navigate to the Sales tab.
- Choose the Invoices.
- Select the invoice activity to view the Status, check the customer's email address for typos or errors.

Also, you can refer to this article for guidance on troubleshooting issues with customers not receiving your invoices via email: Troubleshoot if customers aren't receiving emails from QuickBooks Online.
Finally, refer to this article to learn how to add Intuit's service email addresses to your email allow list: Receive important email messages from Intuit.
If you have further questions about emailed invoices, you can comment below, and we'll respond to you as soon as possible.