Most likely you are running both addons, which isn’t allowed.
- https://www.home-assistant.io/integrations/zwave_js/#can-i-switch-between-the-official-z-wave-js-add-on-and-the-z-wave-js-ui-add-on
- https://community.home-assistant.io/t/switching-z-wave-js-addons-with-minimal-downtime-z-wave-js-official-to-z-wave-js-ui-community/409904
The Server URL in the Z-Wave integration settings will tell you which one you’re using. If it has “core” in the address, you need to follow the above guides. If it has “addon” in the address, then you just need to uninstall the core add-on.