Integer Constraints on Excel Solver Tool

I set the problem up as a test to see how the function worked.

I want to assign three people, (A, B, C), a number between 1 and 3. That means there are 27 possible combinations. I run solver to optimise (what I'm optimising is irrelevant to this question). Solver then proceeds to make tens of thounds of trials. Why is that when there are only 27 possible combinations? Does excel solver trial decimals and round to the nearest integer when considering the integer constraint. How do I limit it to only trying integers?
I cannot paste an image but incase you ask what the constraints are:

By Changing Variable Cells:
$E$2:$E$4

Subject to the Constraints:
$E$2:$E$4 <= 3
$E$2:$E$4 = integer
$E$2:$E$4 >= 1

Solving method:
GRG Nonlinear: selected 1 for all three people
Simplex LP: unable to solve
Evolutionary: does the tens of thousands of trials

Any input would be appreciated.