Dead zone on iPhone 5c after replacing screen assembly.

I replaced the screen assembly on my iPhone 5c.

Now I have a different problem. Everything works just dandy, EXCEPT:

Towards the bottom of the screen (in portrait) there is a horizontal line that is dead to the touch. For example, on the keyboard, I can use the spacebar, but not C V B N M, etcetera.

Three possibilities in my mind: One, when I dropped it, something else besides the glass and digitizer, etc, was damaged.

Two: I did not replace the cables correctly. This seems unlikely. They all "clicked" into place and stayed there.

Three: The digitizer supplied is faulty.

Comments? Which cable/connector could be causing this -- if it is that?