: For workbooks on Tableau Public or certain Server environments, an extract may be required. If the extract is missing or hasn't refreshed, the download might fail.

Sometimes the failure is due to the server environment or network configuration rather than user settings. Permissions - Tableau Help

: If a workbook uses a live connection , you often cannot download it with the data unless you have the specific database credentials.

: Tableau permissions follow a "deny takes precedence" rule. If you are in multiple groups and one group is explicitly denied the download capability, you will be unable to download even if another group allows it. 2. Check Data Source Connections