I am trying to send an invoice to an email address that I know is valid and it will not go through?

I appreciate your time in addressing your concerns about sending invoices in QuickBooks Online (QBO), Matt. I'd love to get to the bottom of this, but I need more details from you.

Did you receive any error messages when trying to send the invoice? I'd also like to know if the invoice isn't going through to a specific or all of your customers. This information will help me identify the root cause of the issue and find an accurate resolution for you.

In the meantime,  I suggest advising your customers to check their junk mail and spam folders. Some email domains may block @intuit.com communications on their servers.

If the email is still not found, clear your email address and re-enter it to refresh and ensure that the email address is accurate.

Here's how:

1. Go to the Gear icon on the top left of your QBO page and select Account and Settings.
2. Click on the Company tab, then select the Pencil icon in the Contact info section.
3. Clear the Company email field and enter the desired address as is, even if it appears correct. 
4. Select Save, then Done. 

Feel free to read this article for complete details: Troubleshoot if customers aren't receiving emails from QuickBooks Online.

I'll share these articles that guide personalizing your sales forms and recording invoice payments once your customer pays.

• Customize invoices, estimates, and sales receipts in QuickBooks Online
• Record invoice payments in QuickBooks Online

Let me know if there's anything else I can do for you. I want to ensure you're well taken care of. I wish you and your business all the best.