We understand how important it is for you to receive invoice emails, Abi. Your detailed overview of this delivery issue you're experiencing is appreciated.
To help narrow down the cause, please confirm if you have already tried the troubleshooting steps outlined in this article. These steps are designed to address common delivery challenges and could help resolve the problem quickly.
If the issue continues after completing those steps, I recommend contacting our Live Support team. They have the specialized tools and expertise to investigate why your invoice emails aren’t delivered, even though your domain and email authentication settings are correctly configured. They can also assist with escalating the issue if necessary.
Here's how to connect with them:
- Inside your QuickBooks Self-Employed (QBSE) account, navigate to the Help menu.
- Choose the Contact Us tab at the bottom of the page.
- Enter your question, keyword, or topic, then click Continue.
- Choose a way to connect with us and follow the prompts.
Alternatively, you can contact QuickBooks support outside your QBSE account by visiting the Contact QuickBooks Team page.
Our customer service hours for phone and chat support every weekday are from 8:00 AM to 7:00 PM. On weekends, chat support is available from 8:00 AM to 6:00 PM.
In the meantime, as a helpful workaround, you may consider manually downloading your invoices as PDFs and sending them directly to your clients outside of QuickBooks. Below is a screenshot illustrating how to export your invoice as a PDF:

You may also find this article helpful if you want to export and run financial reports in the program: Export transactions and get reports in QuickBooks Self-Employed.
I’ll ensure this conversation remains open for any future updates and discussions.