Issues using Clone Stamp tool

I am using the latest version of PS on an Acer Windows computer. I wish to take the pixels from the background layer and copy them over a discolored area in the frame.

I am selecting the clone stamp tool

I am selecting the size of the brush and a hardness of 100%

I am clicking the ALT key and rubbing the brush over and area on the background layer. However when I move the cursor or brush to the area I want to copy to a white circle appears and then, at the same distance from the area I was copying from the crosshairs move but nothing happens.