I have a list that is broken up in different parts. The list is broken up by
blank cells and by text.

My formula works if I only include a part of the sheet

=SUMPRODUCT((Sheet1!A5:A17=A3)*(Sheet1!T5:T17="Gew erbe")*Sheet1!K5:K17)

but not if I include the whole column:

=SUMPRODUCT((Sheet1!A:A=A3)*(Sheet1!T:T="Gewerbe") *Sheet1!K:K)

Any suggestions?