I don’t your your level of experience so forgive if I touch on something that seems obvious.
Assuming you have some basic knowledge, check your collision. If you have it set to something like Pawn it won’t detect you clicks. Change it to custom and select whatever options you want but make sure you have Visibility set to Block.
If you are a bit newer, make sure your input is setup, to include ensuring that you have the right GameMode and that the proper player controller, default pawn and everything else is set up in it. After that check to ensure your input is working by adding in a “printString” node so you are sure.
Second, I can’t see how your blueprint is setup so let me know if this is right. You have a box in a BP with an Onclick event set to the cube. Once clicked it should resize to a desired amount, make sure any variables aren’t at the default 0. If correct, you should just be able to access the set world scale or relative scale node and change it to the desired vector size on the click.
However, when I upgraded to…, I think 4.6, the onclick events stopped working for me and I had to reinstall it. That solved the issue.
You are probably using a variable to control the resize amount; make sure it isn’t set to the default of 0.