Hi there, hangmark.
It could be you've downloaded the QuickBooks Online app instead of QuickBooks Self-Employed app that's why the program prompts you that your account doesn't have access.
Let's make sure that you've downloaded the QuickBooks Self-Employed (QBSE) app. You can install the app using the links below:
Once done, let's try logging in using the same username and password you enter when accessing your QBSE account on a web browser.
To know more about the things that you with QuickBooks Self-Employed, you can visit our FAQ page.
Let me know in the comment section if you have any other concerns or questions. Stay safe and have a great rest of the weekend.