I am able to successfully get the dashboard service up using NodePort. But with nginx-ingress, I keep getting 504 timeout. Here is my ingress configuration. Any thoughts?

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    nginx.ingress.kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
    nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
    nginx.ingress.kubernetes.io/rewrite-target: /
  name: dashboard-ingress
  namespace: kubernetes-dashboard
spec:
  rules:
  - host: dashboard.FQDN
    http:
      paths:
      - backend:
          serviceName: kubernetes-dashboard
          servicePort: 443
        path: /
  tls:
  - hosts:
    - dashboard.FQDN
    secretName: secret_dashboard
status:
  loadBalancer: {}