Hello, aobrist.
Thank you for choosing QuickBooks as your accounting software. In QuickBooks, we need to take note that this integration method is only available for QuickBooks 2019 and newer. For QuickBooks 2015-2018, see: Integrate TSheets and QuickBooks Desktop using the Web Connector.
However, if you meet the requirements when integrating your TSheets in QuickBooks, I suggest contacting our TSheets support team. This way, one of our agents can help you check your profile and verify your credential in the system. To contact our Tsheet support, you can check this article: Contact TSheets support.
To learn more about TSheets set up and integration in QuickBooks, you can refer to these articles:
You can always come back here to the Community. I would be more than glad to help. Have a great day!