Neuvector web ui cannot login - internal server error

Use basic ip address with load balancer. You can also test it with ClusterIP, and use kube proxy to access it. Also check your deployment - if manager and controller are not restarting.

Section for manager in values for helm

manager:
  enabled: true
  resources:
    limits:
      cpu: 250m
      memory: 1000Mi
    requests:
      cpu: 250m
      memory: 250Mi
  svc: # web ui
    type: ClusterIP

next you use this

kubectl port-forward services/neuvector-service-webui 8443:8443 -n neuvector