Service don't have clusterIP, and lowable-workflow-ui is not accessable

[linonetwo]

This is what I modified to my value

host:
  external: workflow.mydomain.xxx
ingress:
  class: "nginx"
  useHost: true
postgres:
  storage:
    storageClassName: "microk8s-hostpath-retain"

It successfully installed, but I found flowable-workflow-flowable-ui service's clusterIP is None:

kind: Service
apiVersion: v1
metadata:
  name: flowable-workflow-flowable-ui
  namespace: workflow
  uid: 60c3abd3-4284-42bb-add8-42b7be8426d4
  resourceVersion: '3731938'
  creationTimestamp: '2023-11-27T09:56:39Z'
  labels:
    app.kubernetes.io/instance: flowable-workflow
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ui
    helm.sh/chart: flowable-6.8.0
  annotations:
    meta.helm.sh/release-name: flowable-workflow
    meta.helm.sh/release-namespace: workflow
  managedFields:
    - manager: kubeapps-apis
      operation: Update
      apiVersion: v1
      time: '2023-11-27T09:56:39Z'
      fieldsType: FieldsV1
      fieldsV1:
        f:metadata:
          f:annotations:
            .: {}
            f:meta.helm.sh/release-name: {}
            f:meta.helm.sh/release-namespace: {}
          f:labels:
            .: {}
            f:app.kubernetes.io/instance: {}
            f:app.kubernetes.io/managed-by: {}
            f:app.kubernetes.io/name: {}
            f:helm.sh/chart: {}
        f:spec:
          f:clusterIP: {}
          f:internalTrafficPolicy: {}
          f:ports:
            .: {}
            k:{"port":8080,"protocol":"TCP"}:
              .: {}
              f:name: {}
              f:port: {}
              f:protocol: {}
              f:targetPort: {}
          f:selector: {}
          f:sessionAffinity: {}
          f:type: {}
spec:
  ports:
    - name: http
      protocol: TCP
      port: 8080
      targetPort: 8080
  selector:
    app.kubernetes.io/instance: flowable-workflow
    app.kubernetes.io/name: flowable-workflow-ui
  clusterIP: None
  clusterIPs:
    - None
  type: ClusterIP
  sessionAffinity: None
  ipFamilies:
    - IPv4
  ipFamilyPolicy: SingleStack
  internalTrafficPolicy: Cluster
status:
  loadBalancer: {}

And I can't access it from https://workflow.mydomain.xxx , why?