This suggests the internal relay is functioning, but there is a fault in the lighting circuit or a blown fuse/breaker downstream.
Proper installation is critical for the photocell to function accurately. Merlin Gerin Multi 9 Ic 2000 P Manual
Connect the two wires leading to the external photo-electric sensor. There is no polarity to observe for the sensor wires. Programming and Calibration This suggests the internal relay is functioning, but