How to allow managed load balancers in kubernetes network policies?

I want to restrict access to namespaces. I’ve added next network policy to my namespace:

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: np-dev-allow
  namespace: dev
spec:
  podSelector: {}
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          purpose: monitoring
    - namespaceSelector:
        matchLabels:
          purpose: ci
    - namespaceSelector:
        matchLabels:
          environmentName: dev

In this policy I’m only allowing traffic from few namespaces. But after that DO load balancer is down and can’t reach nodes, load balancer created by nginx-ingress. How I can whitelist load balancer in network policies?