I'll forward your message to our engineering team, @Aaron.

I appreciate your patience in dealing with this issue. I want to get the invoice delivery issue resolved as soon as possible. This way, your clients will receive the emails without delay.

I know this issue has been around for a while. Please know this is a high priority for us and will continue to be a focus and priority until fully resolved.

The original INV-70915 was already closed, but since other users are still reporting the same issue, we opened a new one for tracking purposes. With this, I'd recommend contacting our Customer Care Team again. You can follow the steps provided by FritzF above. Make sure to reach them within business hours to ensure a swift response.

In the meantime, you can use the workarounds provided by Kevin_C to send your sales forms. 

Feel free to visit our Invoices and payments page for more insights about managing your sales transactions.

Do you need more help completing other tasks in QuickBooks? Please let me know, and I'll assist you with some guides and other pointers. Keep safe.