Am having trouble emailing a regular customer his invoice. I have checked his email address and it is correct.

Hi there, Kevin.

Since the customer's email address is correct, but an email is still not being sent, you may set up your server to accept QuickBooks Online mail server host names and IP addresses.

You can also ask 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.

Here's how:

1. Go to Settings and select Account and settings.
2. Go to the Company section, then select Edit.
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.
   
   
    

You can check out these articles on how to resolve the 'Delivery Server Down' error and how to set up the server to accept QuickBooks Online mail server host names and IP addresses.

• Fix the Delivery Server Down error in QuickBooks Online.
• What to do if invited users did not receive your email invitation in QuickBooks Online.

If you have any additional concerns, please share them with us.