After creating a deployment for a web-application, consisting of pod, internal service and ingress, the ingress can't be created. When executing kubectl apply -f web-app.yaml, I get the error: error when creating "web-app.yaml": Internal error occurred: failed calling webhook "validate.nginx.ingress.kubernetes.io": Post "https://ingress-nginx-controller-admission.ingress-nginx.svc:443/networking/v1/ingresses?timeout=10s": dial tcp 10.100.7.97:443: connect: no route to host

After some retries, it worked surprisingly, but after some changes to the deployment, the same error occurs again.

web-app.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  namespace: development
spec:
  replicas: 1
  selector:
    matchLabels:
      app: web-app
  template:
    metadata:
      labels:
        app: web-app
    spec:
      containers:
      - name: web-app
        image: registry/web-app:latest
        resources:
          limits:
            memory: "128Mi"
            cpu: "500m"
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: web-app-internal
  namespace: development
spec:
  selector:
      app: web-app
  ports:
  - port: 8080
    targetPort: 8080
    protocol: TCP
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations: 
    kubernetes.io/ingress.class: "nginx"
  name: web-app-ingress
  namespace: development
  labels:
    name: web-app-ingress
spec:
  rules:
  - host: web.app
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: web-app-internal
            port: 
              number: 8080

Any clues what the issue could be?