My Doorbell rings when ring door bell detects motion

Hi I installed Ring video doorbell pro 2 on my new home. I have an electronic door bell installed by my builder (model: nicor prcp2). When installing door bell i didn’t install pro power kit which came with the ring doorbell pro 2 and connected to the wires that came with current doorbell. I changed setting in home chime setting to mechanical based on online suggestions. It was working fine until few days back. It is automatically ringing when motion is detected and it is not ringing when ring button is pressed. I have ring alerts, motion alerts and motion detection enabled. I did turn off ring alerts and motion alerts but still it is automatically ringing when motion is detected. Can someone suggest how to turnoff automatic doorbell ring when motion is detected and ring only when doorbell button is pressed. TIA