Hi @RandomDenny ,
I know this is an old and closed topic already, but maybe it will still help someone. I just encountered the same error while removing copies of reports from different workspaces from a workspace. I removed the reports from the app. Having removed the reports I got the same error that some of the dashboard tiles didn't load. The tiles mention that the report doesn't exist or you don't have permission to view it.
The real problem is that the dashboard tries to reference the original reports for the user, which currently is no longer possible, since you hid them from the users. What will solve this error is that you provide an external link in the tile. With the introduction of viewing groups, I have provided users in our organization with multiple apps using viewing groups, which makes redundant copies of reports less of an issue and unnecessary to show in apps (except for live pages unfortunately). You still need them in the workspace though.
I use the original reports in different app to link those tiles to. That takes away the error. But I guess you can use any external url. And of course you may link to a different report or dashboard, or even the dashboard itself if you don't need any link.
Cheers,
Niels
