Sometimes in the new navigation experience the navigation breaks, and users see this screen which doesn't resolve. data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAABNYAAAKfCAIAAAAtkNJ2AAAAA...
Yes, but you not gonna like this...
I added the user to the dataset with read-permission for this perticular user. But we had a case where a user had access to both the app and the Workspace and still had this issue. What I did was to recreate the whole Workspace, add all the dataset and transfer the reports. Then add all the permissions for the users again.
A pain, but it solved the issue. Hope it works out for you.
Best regards
Fabian Witkowski