Hello Jeff P,

Here are a few possible reasons why you're getting this message when sending an invoice using Gmail:

• The security settings on your Gmail might be blocking your emails from QuickBooks.
• Your antivirus software may accidentally block the connection.

Let's be sure to update your QuickBooks Desktop to the latest release. Then, try to email a test transaction to yourself.

If it doesn't work, we can proceed in reviewing your settings and filter the preferences. You can follow step 2 in this article: Fix webmail password issues in QuickBooks Desktop.

If you're getting the same result after the steps above, I'd recommend contacting our Customer Care Team. We will investigate the issue further. 

Here's how you can reach out to us:

1. Click Help located at the top.
2. Choose QuickBooks Desktop Help.
3. Enter a brief description of your issue and click Continue.
4. You can choose Message an Agent or Talk to a Specialist.

Let me know in the comments below if you have any additional questions. Thanks.