Browser-Mod pop-up with hui-elements issue

I have a floorpan that and uses picture-elements to interact. I want to have an icon and, when pressed, pops-up an entity card. I’m trying to do it like the follow but nothing is popping up. Anyone know what I’m doing wrong?

          - type: state-icon
            entity: switch.guest_bedroom_fan_switch
            style:
              left: 10%
              top: 52%
              opacity: 100%
            tap_action:
              action: call-service
              service: browser_mod.popup
              data:
                title: Guest Bedroom
                content:
                  type: custom:hui-element
                  card_type: entities
                  entities:
                    - light.guest_bedroom_fan_light
                    - fan.guest_bedroom_fan