I get an error message when i try to send an invoice "firewall/internet connection/un or password/or server settings" are wrong. I can email a statement.

Let's perform some troubleshooting steps to isolate this issue, @mking12.

I suggest running the repair tool to fix this error in your QuickBooks Desktop (QBDT) right away. This way, you'll be back in working order. Let me guide you how.

Before doing so, I recommend to back up your company file first. Once done:

1. Restart your computer.
2. Open the Windows Start menu and select Control Panel.
3. Click the Programs and Features then Uninstall a Program. 
4. Choose QuickBooks from the list of programs, then click Uninstall/Change.
5. Click Continue, or Next.
6. Select Repair, then Next
7. Click Finish when done,
8. Then update your QBDT to have the recent fixes and security update.

For more information, please check this great article: Repair your QuickBooks Desktop for Windows

Then, in case you need to remove a credit from an invoice, check this article for details: Remove or unapply a credit from an invoice or bill.

I'll be around to help whenever you need assistance. Stay safe!

I tried twice with the same results.  I can send statements but not invoices. 

Thanks for keeping us updated, mking12.

Aside from what was already shared in the first reply, I have other options to recommend. 

Also, based on the error message that you're getting, we'll have to make some changes or configure your internet or firewall settings in QuickBooks. 

First, let's restart your computer. Dong this usually resolves issues or problems when using web-based features, including emailing transactions.

Second, let's operate Internet Explorer in Compatibility View. Here's how:

1. Open and Internet Explorer browser.
2. Go to the Gear icon at the top right and then choose Compatibility View settings. You can also go to the Tools drop down (or press Alt+T on your keyboard to access the Tools option).
3. Proceed to the Compatibility View settings screen.
4. Then, check the Display all websites in Compatibility View box and click Close.

Once done, go back to QuickBooks and send an invoice again to check if you're able to it. 

If you're still getting the same error message, please go to these articles and follow the other recommended steps:

• Verify and Troubleshoot QuickBooks Desktop and Internet Explorer settings
• Configure Internet Explorer to work with QuickBooks Payments and related applications

Please continue to add a reply below to keep us posted. We'll keep revisiting this thread to help you again.