What does the "Background Tasks" view (under "Administration" --> "Maintenance") show for the time you expect the extract to run? If you manually start the extract on the server, does it work?
Did you publish the workbook with the option 'Include External Files' unchecked ?
Tableau has this option checked by default when you submit a work connecting to excel files. If you publish your workbook in this way, a snapshot of source file will be attached inside the workbook and every time you hit refresh, the workbook is not connecting any outside source but this snapshot. Probably that's why you cannot get refreshed data even you kick off the task mannually.
Jason Halmagy wrote:
The way I publish Excel or CSV files is to use the UNC (Universal Naming Convention) for the path to the file. UNC looks something like: \\[servername or ipaddress]\sharedfolder\filename.xlsx.
Be sure that the network service Active Directory account that Tableau Server uses has read/write permissions to that sharedfolder and can access the folder.
With those elements in place, then you can publish to the server without checking the 'Include External Files' box, since the server will be able to read the file directly. If you are publishing an extract of the Excel file, then the server will be able to schedule a refresh, since it has access to the underlying file location.
Last, have your server admin check the error log (or if you are a site admin, you can check it out under background tasks). After requesting a 'run now' update of the extract, see if the extract is successful or not. The error message should help you figure out what problems you might be having in your setup.