Nothing has changed, Renne. You can run the QuickBooks Install Diagnostic Tool and update QuickBooks to fix the error you've got. Let me guide you further with complete steps.

Before anything else, are you using Outlook as your email? While waiting for your response, you can run the tool I mentioned earlier. It will help you email the receipt to your customer successfully.

1. Close QuickBooks and download the QuickBooks Tool Hub.
2. Open the file you downloaded (QuickBooksToolHub.exe).
3. Follow the on-screen instructions and agree on the terms and conditions.

Now, run the QuickBooks Install Diagnostic Tool. Here's how:

1. Open the QuickBooks Tool Hub and select Installation Issues.
2. Choose QuickBooks Install Diagnostic Tool and let the tool run. It may take up to 20 minutes to complete.
3. Once the tool finishes, restart your computer and open QuickBooks Desktop. Then, open your data file.

Finally, update your QuickBooks to the latest release to ensure you have the most recent fixes and security updates.

1. Go to the Help menu.
2. Select Update QuickBooks Desktop.
3. Click the Update Now button and hit Get Updates.
4. Close and reopen QuickBooks.

Additionally, you can visit this article for tips about emailing sale forms: Send them individually or as a batch. 

Reply to this thread if you've got other concerns or need help fixing unexpected errors in QBDT. I'm ready to help you.