I have ingress controller file with rules.

I wanted to add default backend:

defaultBackend:
  service:
  name: nginx-errors
    port:
      number: 80

so I put that in spec before rules, and I click update (I am usind UI for that). When I reopen config file there is no sign of default backend. I have used those config files for creating default backend service and pod: https://github.com/kubernetes/ingress-nginx/blob/main/docs/examples/customization/custom-errors/custom-default-backend.yaml.

What might be wrong?