We are using Tableau Server version 10.1.0, when permission was not granted to a dashboard error message receive with and without "?:embed=y" as follow:
with "?:embed=y": Resource not found. Please check the URL and try again
without "?:embed=y":That page could not be accessed. Either the view does not exist or you do not have the necessary permissions
Our environment using embed link, question is that we would like to see the error message as number 2 when is due to permissions issue rather error message number 1 which might confuse people due to dashboard typo in the URL. Is there any possible to view error message as from number 2 due to permission issue with "?:embed=y"?
The first error occurs because there is no user authenticated so Tableau Server can't spin up the error message shown in the second. This behavior is by design and can't be changed. You could however create a feature request in the Ideas section and encourage others to vote it up!