The Site Content URL Name that needs to be specified is dependent on how Tableau has been configured and deployed. Each instance of Tableau is deployed with a default site but additional sites can be deployed. When unsure if additional sites have been deployed, the URL used to reach the Tableau content provides insight.
Default URL format
Additional Site URL format
In the above example, contenturl would be replaced with the actual site name.
If your Tableau URL follows the convention of the Default URL format, then the Site Content URL Name is Default. Otherwise, it is the site name that replaces the contenturl portion of the Additional Site URL format example above. Be aware, the Site Content URL Name is a case-sensitive parameter.