Hi there, @rankhornjp.

Let me lend a helping hand with sending invoices via email in QuickBooks Desktop.

There are a few possible reasons why this is happening:

• The email preference being set incorrectly.
• A damaged QuickBooks installation.
• Domain admin was blocked.
• Account security settings from your email provider.

To isolate the issue,  you want to make sure your QuickBooks Desktop software is in its latest release. QuickBooks periodically provides maintenance release and product (software) updates to fix emailing concerns, add features and enhancements, and update compliance information.  Once done, you can check the web mail's settings in the preferences.

Here's how:

1. At the top menu bar, click Edit.
2. Choose Preferences.
3. Click Send Forms on the left panel.
4. Under My Preferences tab, select the email account you're using.
5. Click Edit.
6. Mark the SSL box, or just select Default.
7. In the Server Name field, make sure the server name matches your email provider's settings.

You can find out more details about connecting your email address for invoicing here: Connect your email to QuickBooks Desktop. 

I'm sure you'll find our articles helpful in case you need help recording other transactions for your customers. You can browse for one in our Sales and customers topic. 

I'll keep this thread open in case you have other questions with the Desktop platform. I'm always here to help.