Thanks for the explanation.
The SUMIFS function is arranged as follows, in general terms:
in other words,
SUM (add up total for all) of
date > H5
date < H6
where H5 holds the start date, and H6 holds the end date.
Now in your case, there is an A5 reference, and I don't know what that is supposed to be.
In practice that formula would look like this, literally and not generally: