This is because excel is local file and tableau server wont be having to access to that file thats why your data is not getting refreshed
Check the below link
Hope this helps
Plz mark this answer as correct and helpful to close the thread.
first check your database connection.
find out from where you are fetch the data
check the database is LIVE or Extracted
I'm not using a server or a database connection. I'm just using a regular tableau file that connects to the excel file, but when I save the excel file and then hit the refresh symbol in tableau it doesn't refresh the data from the saved file.