Connecting excel pivot table using power bi dataset

Hi Everyone,

In excel, I selected pivot table -> from power bi then was able to connect excel with the power bi dataset.

I'm thinking of creating a pivot table to show how many applications come from each marketing channel (ie. email, website, store) on each day. However, when I was trying to drag Total number of pplications from pivot table field to 'Values', an error message popped up

Can anyone let me know what has gone wrong please? if the worksheet is in excel, I don't have an issue. It's my first time getting data from power bi in excel so I got a bit confused.

Thank you!