There are a few scenarios that I can provide, editebeck.
There are not limited clients that you can have in viewing your 1099s. It's possible that the client didn't file the forms yet. You'll get a confirmation that they already filed your tax form. We can log out and log back in to refresh.
Let's log in to your QBSE account and then from the left menu, click Clients. Check if you can now see the other client and then go to the Tax forms tab to view your 1099.
If you need more help you can always reach out to the Community.