Differential amp v1.2

Need some help.
I’m trying to read a signal from a pressure sensor with my controllino MAXI using the diff amp v1.2. When I connect everything, there is a 4v potential between the input pins of the amplifier. Why? Even without the sensor connected to the amp, there is a 4v output from the amp on the signal pin. What am I doing wrong? Any help would be much appreciated