Hi Marcus,
Let's get this error sorted out so you can continue linking an application.
You may be experiencing some troubleshooting steps that resulted in the error you received. With that, let's run some troubleshooting steps to fix it.
To begin with, let's connect an application through a private window. You can use these keyboard shortcuts to open one:
If you're able to get rid of the error, you can browse regularly and clear its cache. Piled browsing history can slow the page we're working on. Hence, we experience unexpected issues.
You can also use a different supported browser like Google Chrome, Mozilla Firefox, Microsoft Edge, or Safari.
Moreover, if you want to change the admin of the application, you can check this article: Change Admin of the app connection.
I'm always around whenever you have concerns about linking an application.
You have clicked a link to a site outside of the QuickBooks or ProFile Communities. By clicking "Continue", you will leave the community and be taken to that site instead.