ADC on Xiao + Multiplexer

I dont know where to ask, this is something new in the market too.
So my Xiao somehow reading analog data the same. there is voltage range 0-3.3 and its already checked with multitester. because of the analog input need 16 pin, im using multiplexer MUX74HC4067 and the input going to A0. when reading pin that connected to the voltage source, its showing the same analog all the time. but if i check it again, its shows different voltage. resolution already set to 12 bit. is there anything hardware-wise that make this cannot be used? or is it my program?

#include “MUX74HC4067.h”

MUX74HC4067 mux(5, 4, 3, 2, 1);

void setup()
mux.signalPin(A0, INPUT, ANALOG);

void loop()
for (byte i = 0; i < 16; i++)
int temp =;
Serial.println("Cell " + String(i) + ": " + String(temp));

Hi Ghafariz,

Please tell me where you got “MUX74HC4067.h”.
What exactly does “shows different voltage” mean?