Circuit with Zener-Diode not working (simulation do)
Your mistake is in understanding how a zener diode works. It just doesn't turn into a clamp at 3.6 volts and below this voltage looks like an open circuit. 

If you read the data sheet you will see that this zener (MMBZ5227) with a reverse voltage of 1 volt applied will take a current of 15 uA. Now imagine what happens as you approach the zener voltage (where it is taking 20 mA). The 15 uA might double or quadruple at 2 volts and this current flows through the 100 k resistor and produces an error voltage. As you get higher in voltage this current rapidly increases towards the 20 mA current.



Picture source.

If you look at the knee point in the above picture you can see that current is conducting at lower voltages. This has the effect of lowering the 49.9k resistor value as applied voltage is increased.