Ring Doorbell generation 2: Mechanical doorbell not working

Hi all, Recently i installed my newly purchased Ring doorbell gen. 2 and hard-wired it to my existing doorbell setup, which is an 8volts AC doorbell adapter and a mechanical doorbell ( a ringing bell ). Basically by replacing my old doorbell button with my Ring doorbell gen. 2. Took off the wires of my old doorbell button and connected them to my Ring doorbell gen.2. I did not use a resistor, since from the install instructions i understand that a resistor only is required when not using a mechanical doorbell in your setup, since the resistor replaces the mechanical doorbell. I also did not use a diode, since my doorbell is not digital. My Ring doorbell receives power, indicates in the app that it is hardwired, but when i press the doorbell, my mechanical bell is not working. It was working perfectly before i installed my Ring doorbell gen. 2 Any ideas on this? Kind regards, Michiel