The emailed invoices might have posted on their Spam or Junk folders, allanf1234abcd.
Please ask your customers to check these folders to verify if it's posted there or not. If the email is still not there, let's clear and then re-enter your email address.
Here's how:
- Go to the Gear icon and then select Account and Settings.
- Choose Company from the left menu and click the Contact info section.
- Clear and re-enter your email address.
- Select Save and Done.
- Send yourself a sample invoice, afterwards.
You can also check this article for other troubleshooting steps: 3 solutions for when customers aren't receiving your emails.
Let me know how this worked in your end. I'll be around to help.