Thanks for letting us know about the issue you're having, @Trufflepig. We can review your Firewall/Antivirus Settings and Email client configuration to ensure they're correctly set up and not causing any filtering based on your server rules.
If the issue persists after trying the solutions stated above and in this article, I recommend contacting our Live Support Team. They have the necessary tools to access your account in a private setting and investigate further about the issue. They can also create a ticket for investigation if needed.
Here's how:
- Go to the Help menu.
- From the Search tab, select any article.
- Click Contact Us.
- Pick a topic or enter your concern, then select Continue.
- Choose Chat with us or Have us call you.
For more details about the support schedule, please see the article: QuickBooks Online Support.
Additionally, visit these articles as your future reference in customising invoices and recording payments in QuickBooks:
Stay in touch by replying to this thread with any follow-up questions about sending invoice emails to your customers, @Trufflepig. We're always here to help you.
