I have setup KOPS cluster. also have deployed nginx ingress controller and behind two demo app.

have deployed cert manager also and its running perfect.

but when I am create issuer and hit command as below,

kubectl get certificate.cert-manager.io --all-namespaces

got not resources found error.

issuer.yml content

apiVersion: cert-manager.io/v1alpha2
kind: Issuer
metadata:
  name: ssl-prod
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: hardik.patel@example.com
    privateKeySecretRef:
      name: ssl-prod
    solvers:
    - selector: {}
      http01:
        ingress:
          class: nginx

my ingress yml is as below,

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-testing
  annotations:
    kubernetes.io/ingress.class: nginx
    cert-manager.io/issuer: "ssl-prod"
    #    nginx.ingress.kubernetes.io/ssl-redirect: "true"
spec:
  tls:
  - hosts:
    - nginx.test.in
    secretName: nginx-test-in-tls

spec:
  rules:
  - host: nginx.test.in
    http:
      paths:
      - path: /
        backend:
          serviceName: nginx-demo
          servicePort: 80

what is way to troubleshoot and resolve?