KbCheck is not working

Hello, I have a trouble with getting KbCheck working, which is the Psychtoolbox function.

I think I have done everything correctly but, not only the KbCheck itself is not working, but also the sca at the end doesn't work too.

So when the stimuli end, the screen holds and I have to type sca to my command line again.

I want to fix this problem. Glad if someone can help me.

while ~KbCheck
    
    
    coordsX = outX{j};
    coordsY = outY{j};
    
    % Draw the dot to the screen
    Screen('DrawDots', window, [coordsX(i); coordsY(i)]/20 + startPos, dotSize, dotColor, [0 0], 1);
    
    % Flip to the screen
    vbl  = Screen('Flip', window, vbl + (waitframes - 0.5) * ifi);
    
    % Increment the time
    i = i + 1;
    
    if i > size(coordsX,2) % if reached the end of that set of coordinates, move to next trial
        j = j+1; i = 1;
    end
    
    
end

% Clear the screen
sca;