Hi,
Where did you save the Excel Workbook?
Did this problem appear in all Excel Workbooks?
What kind of file format did you use?
I suggest you try to create a new Workbook in desktop with simple data and then open the saved Workbook and copy and paste the Range in PowerPoint.
If this problem only appear in specific Workbook, please check the Excel file format, make sure you're using .xlsx file.
Then remove all password or permission for authentication in Excel Workbook.
Just checking in to see if the information was helpful. Please let us know if you would like further assistance.
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.