incorrect error that fields are missing in grafana organization create

I am trying to create organizations in grafana through API calls. but i was getting some error on user and password related. but i used to login through basic authentication only. could you please help me anyone on this to figure out.

i used separate istio ingress-gateway and virtual service to hit the grafana.

grafana version : 7.5.3

istio-gateway:

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: grafana-gateway
  namespace: istio-system
spec:
  selector:
    istio: ingressgateway
  servers:
  - hosts:
    - grafana.aws-digital.cffs.com 
    port:
      name: http
      number: 80
      protocol: HTTP
  - hosts:
    - grafana.aws-digital.cffs.com 
    port:
      name: https
      number: 443
      protocol: HTTPS
    tls:
      credentialName: istio-tls-cert
      minProtocolVersion: TLSV1_2
      mode: SIMPLE

virtual-service:

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: grafana-virtual-svc
  namespace: default
spec:
  hosts:
  - grafana.aws-digital.cffs.com
  gateways:
  - istio-system/grafana-gateway
  http:
  - match:
    - uri:
        prefix: /
    route:
    - destination:
        port:
          number: 3000
        host: prometheus-default-grafana

the curl command i used to create organizations in grafana :

curl --location --request POST 'https://grafana.aws-igital.cffs.com/ops/portal/grafana/admin/orgs' 
--header 'Host: grafana.aws-digital.cffs.com' 
--header 'Accept-Encoding: application/json' 
--header 'Accept: application/json' 
--header 'Content-Type: application/json' 
--header 'Authorization: Basic YWRtaW46cHJvbS1vcGVyYXRvcg==' 
--data-raw '{
  "name":"test"
}'

i added all headers and in body i added only org name. all looking fine but i was getting this error :

[{"fieldNames":["User"],"classification":"RequiredError","message":"Required"},{"fieldNames":["Password"],"classification":"RequiredError","message":"Required"}]

can anyone help me where i did mistake. your response will be appreciated. thank you