I am aunable to send an invoice. I get an error message that it can't authenticate and to try a new browser

Welcome to the Community, @jacktbandy.

It's possible that Intuit isn't added as a Trusted Sites in your Internet Explorer option that's why you've received such error message. Let's configure the settings of your IE so you'll be able to send invoices successfully.

Here's how:

1. Open your Internet Explorer browser, then select the Gear icon.
2. Click Internet options.
3. Go to the Security tab, then select Trusted sites.
4. Click the Sites button, and enter https://*.intuit.com in the Add this website to the zone field, then select Add.
5. Then, repeat the steps for https://*.quickbooks.com.
6. Click Close and select Custom level..., then scroll down to Miscellaneous.
7. Under Access data sources across domains, choose Enable, then click OK.
8. Click Apply then OK to close the Internet Options window.
9. Restart Internet Explorer to apply the changes.

Here's an article you can read for more details: Configure Internet Explorer.

Once done, you can now send invoices to your customers. 

You might want to read this article to know how to manage invoices: Common questions about paying invoices online.

Please keep in touch if there's anything else I can do to help you succeed with QuickBooks. I've got your back. Have a great day.