I do not understand the question with the activity. I have an upload file button.
With the rule that I posted before.
And when I add a storage bucket it works. Then I try to publish the App or try to see the preview and it shows me the previous error message.
I can only drop storage bucket into the storage bucket field. So I really do not understand this error message and believe it is a bug since UiPath Apps becomes more and more buggy.