liudr:
I guess you didn't solder the male pins to the display. Did I win a price?
On a second look maybe you did solder the pins. The picture was not good enough to convince me but since you didn't say anything, I take it as yes you soldered the pins.
Your breadboard is very small, but you have not used the other half of the board. There's plenty of space to set up a potentiometer.