Magento 2 Email Template New Invoice not updating

I have an email template within my Marketing > Email Templates section called New Invoice. When I click to view previous I can see the template working within the browser no problem at all. The issue however, is when I send the New Invoice email to my email, the email says:

We're sorry, an error has occurred while generating this content.

I think the issue must be the wrong template is being called because even when I only have:

{{template config_path="design/email/header_template"}} {{template config_path="design/email/footer_template"}} 

within the email I still get the same problem. Any help would be appreciated.