"Service: Service is required." - Unable to create jira service desk project issue


I am trying to create a Jira service desk project issue using v2 rest API. I am passing all mandatory fields value but Jira throwing below error.

responseStatusCode : 400

    "errorMessages": [
        "Service: Service is required."
    "errors": {}

Sharing the data below,

Data sent to create the service desk incident,

  "fields": {
    "project": {
      "key": "GSD"
    "issuetype": {
      "name": "Incident"
    "customfield_10402": "test",
    "customfield_12608": {
      "id": "15300"
    "summary": "Test Ticket Please ignore - Jira Testing",
    "description": "this is description"

where the customfield_10402 is a string field and the customfield_12608 is a dropdown field.

Project details :

"projectCategory": {
            "self": "https://domain.atlassian.net/rest/api/2/projectCategory/10400",
            "id": "10400",
            "name": "Service Desks",
            "description": "Customer facing service desk containers, sitting behind single support portal site"
        "projectTypeKey": "service_desk",
        "simplified": false,
        "style": "classic",
        "isPrivate": false,
        "properties": {}