Besides the update of Tableau Server, has anything changed in your computer setup recently? For example, install or uninstall some drivers on the computer running Tableau Desktop or Tableau Server? Or, some change made to your MS SQL Server?
Is your published data source an extract or live?
You can check out this article, which might help: One or More Views on the Dashboard Are Blank After First Extract Refresh from MS SQL Server Database | Tableau Software
The error message is a warning that some of your calculations reference the excel file, my guess is that it isn't published to the server? So, you'll want to make sure your Server Run As User can access the location of that excel file, and check the info here to make sure the path is right: Updating Underlying Data in a Tableau Server Workbook That Uses a Live Connection to Excel | Tableau Software
If none of the above solves it, I'd recommend you reach out to Technical Support: Support Case | Tableau Software for a proper investigation. You'll want to include the error message (including the one you mention getting from your published data source.) and they will probably need logs also.
Hope this helps!