It’s a common problem and the solution is always the same:
You have to enlarge your view of the screen to the max. Then see the little wires that stick out of the boxes. They are NOT alike.
Best you post a screenshot or say the name of the mine.
If you compare what you did to the solution of the maps for this location, you will see that you put boxes where boxes belong, but not the right box in the right place.
The wires that stick out have to match the template, where the current is supposed to flow.
And then you have blue and red ones sometimes, that has to match, too.
As you posted in Detective 4 event, I show you a screenshot of my game there
You see that the box on top on the right has wires to the right and down.
Directly under that one, the next box has wires up and left. And so on. The wires must match where the current flows.
So, in short: If you place any box with the wrong wires on a box-place where that one doesn’t belong, you haven’t placed it „correctly“.