Hello there, serenaruddeger.
I understand that we need to see our paystub. I'd like to know first the exact error message when you go to workforce.intuit.com and sign in. If it says incorrect username or password, you'll want to reset it by clicking I forgot my user ID or password, then simply follow the on-screen steps.
Another possible reason why you encountered error is because you haven't successfully set up your account. Your employer will send you an invitation so you can access your paystub online. We need to open that email and click on the Get access to paychecks to accept the invitation. Once done, you'll be able to view your data online.
Aside from that, you can always reach out to our Chat Support Team. They can check what's causing the error and report it if needed.
You can read this article to know more on how you can view your paychecks and W-2s online in QuickBooks Workforce.
Please comment below if you need more assistance with this. Keep safe!