I'm trying to establish a websocket communication through ambassador but my client is throwing a 503 service unavailable. Im attaching my ambassador and server service configuration.

I'm using this yaml file from ambassador : kubectl apply -f https://getambassador.io/yaml/ambassador/ambassador-rbac.yaml

kind: Service
apiVersion: v1
metadata:
  name: proxyservice
  annotations:
    getambassador.io/config: |
      ---
        apiVersion: ambassador/v1
        kind:  Mapping
        name:  proxy_mapping
        prefix: /stream
        service: stream
        use_websocket: true
spec:
  selector:
    app: proxy
  type: LoadBalancer
  ports:
  - protocol: TCP
    port: 80
    targetPort: 5000

---
apiVersion: v1
kind: Service
metadata:
  labels:
    service: ambassador-admin
  name: ambassador-admin
spec:
  type: NodePort
  ports:
  - name: ambassador-admin
    port: 8877
    targetPort: 8877
  selector:
    service: ambassador
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: ambassador
rules:
- apiGroups: [""]
  resources: [ "endpoints", "namespaces", "secrets", "services" ]
  verbs: ["get", "list", "watch"]
- apiGroups: [ "getambassador.io" ]
  resources: [ "*" ]
  verbs: ["get", "list", "watch"]
- apiGroups: [ "apiextensions.k8s.io" ]
  resources: [ "customresourcedefinitions" ]
  verbs: ["get", "list", "watch"]
- apiGroups: [ "networking.internal.knative.dev" ]
  resources: [ "clusteringresses", "ingresses" ]
  verbs: ["get", "list", "watch"]
- apiGroups: [ "networking.internal.knative.dev" ]
  resources: [ "ingresses/status", "clusteringresses/status" ]
  verbs: ["update"]
- apiGroups: [ "extensions" ]
  resources: [ "ingresses" ]
  verbs: ["get", "list", "watch"]
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: ambassador
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: ambassador
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: ambassador
subjects:
- kind: ServiceAccount
  name: ambassador
  namespace: default
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: authservices.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: authservices
    singular: authservice
    kind: AuthService
    categories:
    - ambassador-crds
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: consulresolvers.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: consulresolvers
    singular: consulresolver
    kind: ConsulResolver
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: kubernetesendpointresolvers.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: kubernetesendpointresolvers
    singular: kubernetesendpointresolver
    kind: KubernetesEndpointResolver
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: kubernetesserviceresolvers.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: kubernetesserviceresolvers
    singular: kubernetesserviceresolver
    kind: KubernetesServiceResolver
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: mappings.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: mappings
    singular: mapping
    kind: Mapping
    categories:
    - ambassador-crds
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: modules.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: modules
    singular: module
    kind: Module
    categories:
    - ambassador-crds
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: ratelimitservices.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: ratelimitservices
    singular: ratelimitservice
    kind: RateLimitService
    categories:
    - ambassador-crds
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: tcpmappings.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: tcpmappings
    singular: tcpmapping
    kind: TCPMapping
    categories:
    - ambassador-crds
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: tlscontexts.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: tlscontexts
    singular: tlscontext
    kind: TLSContext
    categories:
    - ambassador-crds
---
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: tracingservices.getambassador.io
spec:
  group: getambassador.io
  version: v1
  versions:
  - name: v1
    served: true
    storage: true
  scope: Namespaced
  names:
    plural: tracingservices
    singular: tracingservice
    kind: TracingService
    categories:
    - ambassador-crds
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ambassador
spec:
  replicas: 1
  selector:
    matchLabels:
      service: ambassador
  template:
    metadata:
      annotations:
        sidecar.istio.io/inject: "false"
        "consul.hashicorp.com/connect-inject": "false"
      labels:
        service: ambassador
    spec:
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchLabels:
                  service: ambassador
              topologyKey: kubernetes.io/hostname
      serviceAccountName: ambassador
      containers:
      - name: ambassador
        image: quay.io/datawire/ambassador:0.80.0
        resources:
          limits:
            cpu: 1
            memory: 400Mi
          requests:
            cpu: 200m
            memory: 100Mi
        env:
        - name: AMBASSADOR_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        ports:
        - name: http
          containerPort: 8080
        - name: https
          containerPort: 8443
        - name: admin
          containerPort: 8877
        livenessProbe:
          httpGet:
            path: /ambassador/v0/check_alive
            port: 8877
          initialDelaySeconds: 30
          periodSeconds: 3
        readinessProbe:
          httpGet:
            path: /ambassador/v0/check_ready
            port: 8877
          initialDelaySeconds: 30
          periodSeconds: 3
      restartPolicy: Always
      nodeSelector:
        agentpool: apiman
      securityContext:
        runAsUser: 8888