Internal Error when calling zoneRankings in API/v2

My request

{
  characterData {
    character(name: "경력직자택경비원", serverSlug: "아즈샤라", serverRegion: "kr") {
      hidden
      id
      canonicalID
      classID
      zoneRankings(zoneID: 26, partition: 2)
    }
  }
}

And i got this response.

{
  "errors": [
    {
      "message": "Internal server error",
      "extensions": {
        "category": "internal"
      },
      "locations": [
        {
          "line": 8,
          "column": -17
        }
      ],
      "path": [
        "characterData",
        "character",
        "zoneRankings"
      ]
    }
  ],
  "data": {
    "characterData": {
      "character": {
        "hidden": false,
        "id": 56070466,
        "canonicalID": 56070466,
        "classID": 10,
        "zoneRankings": null
      }
    }
  }
}