Dusk to Dawn not enough light to turn off
Did you leave it energized continuously for 48 hours before condemning it?   Many light sensors these days have a learning feature, where they know what "24 hours" is, and measure the brightest and dimmest times of day reagardless of solarization in absolute terms... and learn to turn the light on for the dimmest 8-14 hours.  If your sensor doesn't have this feature, get one that does.

Unfortunately people who don't realize this feature exists, get impatient with them and interrupt their power so frequently that they never get a chance to store 48 hours worth of data.  (the memory isn't non-volatile; NVRAM costs money, and the chip that does this feature wholesales for like 14 cents. It's in a lot of even low-end sensors.) 

I have installed a $6 Walmart-tier sensor in a very shaded location on the back of a porch because that is where the receptacle is... The first day it was on continuously, but I left  it alone; 48 hours later it was acting exactly right.