Form w-4 info: Taxpayer YTD salary must be entered

In smart check, TT is saying:

 

Form w-4 info: Taxpayer YTD salary must be entered

 

What is this?

Am  I supposed to go into my most recent paystub and get the YTD Net Pay?

Or am  I supposed to go into my most recent paystub and get the YTD Earnings?

Why?

Thanks.

Mac