What is happening
On the Z2, vibration is usually a motor communication issue rather than anything mechanical. Motors vary slightly, and the motor driver can overcorrect. A small correction usually settles it.
Step 1: Does it shake without beans?
Run the grinder empty. If it only vibrates with beans in it, a burr may not be fully seated. Open the grinder, remove the rotating burr, clean underneath, and reseat it (see Troubleshooting: Stuck Burr, Tapping Sounds, and Stuck Beans on the Z2).
Step 2: Recalibrate the motor
Follow Troubleshooting: RPM Knob Not Working or Clicking (Motor Recalibration). Make sure the grinder is fully assembled first.
Still vibrating?
If these steps do not work, please contact support at info@zerno.co with a short video.