Hello there, arborine. Welcome to the Community—it's great to have you here. There are a few reasons why sales forms aren't sent to a Hotmail account. Don’t worry—we’ll walk through the steps together to ensure they'll reach their destination smoothly.
If you mean the invoice is undelivered, you'll see its status as Undeliverable in QuickBooks Online. This can occur if the email address is incorrect or if there is a temporary issue with the server.
Here's how to check its status:
- In the Dashboard or My apps, select the Sales & Get Paid tab.
- Go to Invoices and locate the transaction from the lists.
- Review whether it has been sent or not in the Status column.
- If there are delivery issues, select the entry and use the drop-down beside their name to verify that the email address is correct.

Once confirmed, you can ask them to review their junk or spam folders to look for the sent entry. If nothing is found, move on to Steps 3 and 4 in this article to address potential configuration issues: Fix undelivered invoices.
On the other hand, you can refer to this material for guidance if the form was sent but not received by your customer: Troubleshoot if customers aren't receiving emails from QuickBooks Online.
With the instructions above, you should be able to send invoices successfully to a Hotmail account. If you have more questions or need further assistance, please reply below. We’re here for you every step of the way—getting you back to business is what we’re all about.