1.Check the formatting of column headers: make sure all column headers are formatted as text
2.Check if you have hidden rows or columns. Unhide these by selecting Format >> Visibility >> Unhide rows or Unhide columns.
3.Verify if data is being sorted in ascending or descending order. Select Data >> Sort & Filter >> Sort.
4.Check that you are selecting the right data range. Select Data >> Data tools >> Data validation to ensure the right data range is being used.
5.Ensure that no blank cells, text, or special characters are present in the data range.