Why are none of my emailed invoices being received by customers? It says they have been sent on QB but not being received.

If customers are not receiving invoices sent through QuickBooks, it could be due to incorrect email addresses, the invoices being marked as spam or their email providers may have blocked our address. Let's perform some troubleshooting steps to fix the issue.

For the initial solution, you'll want to reset your email address if you recently imported data into a QuickBooks Online.
Here's how:
 

1. Go to the Gear icon , then select Account and settings.
2. From the Company section, select Edit icon in Contact info.
3. Review each email address and make changes as needed.
4. Select Save and Done.
    

If the process above didn't work for you, I suggest asking your customers to check their junk mail and spam folders. If the email is still not found, clear it and then re-enter your email address.

1. Go to Gear icon and select Account and settings.
2. From the Company section, then select Edit icon in Contact info.
3. Clear the Company email field and enter the desired address as is, even if it appears correct. (Note: Be sure not to use any extra characters or spaces before, within, or after the address you enter).
4. Select Save, then Done.
5. Send yourself a test transaction.
6. If you still don't receive the email, try using a different email address that has a different domain (for instance, if you were using a Gmail email address, try a Hotmail or Yahoo address instead).
    

You can also follow the Solution 3 in this article for additional fix: Troubleshoot if customers aren't receiving emails from QuickBooks Online.

Once you've successfully sent an invoice and are ready to receive payments, you can refer to this article for future guidance: Record invoice payments in QuickBooks Online.

Please let me know by replying this thread if you have clarification or additional concerns in managing your invoices. I'm always here to help you.