To create a forecast, select a timeline series of dates or numbers, and a numerical values series of the same size.A forecast ...

To create a forecast, select a timeline series of dates or numbers, and a numerical values series of the same size.A forecast can't be created because the data you selected:• Contains timeline and values series that aren't the same size.• Contains too many cells.• Is linked to an external location that is not accessible, or the link is broken.• Doesn't contain any numbers, and the text cannot be aggregated unless COUNT or COUNTA are selected.