Cannot query exemplars

Hello,

I have both prometheus and grafana running as docker containers bound to the same network.
Prometheus: v2.26.0
Grafana: v7.5.2

When I try to enable examplars on my query I receive the following error:

{"message":"posts not allowed on proxied Prometheus datasource except on /query, /query_range, /series and /labels"}

with HTTP status code 403

However, when I execute the same query in Prometheus api via

curl -X "POST" -G "http://localhost:9090/api/v1/query_exemplars?query=request_total&start=1617286939.565&end=1617290539.565&step=14" | jq .

I see an appropriate response.

{
  "status": "success",
  "data": [
    {
      "seriesLabels": {
        "__name__": "request_total",
        "group": "test",
        "instance": "192.168.1.198:9464",
        "job": "node",
        "url": "/collection/"
      },
      "exemplars": [
        {
          "labels": {
            "trace_id": "234234234234234234234"
          },
          "value": "1",
          "timestamp": 1617289577.361
        }
      ]
    },
    {
      "seriesLabels": {
        "__name__": "request_total",
        "group": "test",
        "instance": "192.168.1.198:9464",
        "job": "node",
        "url": "/get/"
      },
      "exemplars": [
        {
          "labels": {
            "trace_id": "234234234234234234234"
          },
          "value": "1",
          "timestamp": 1617289577.361
        }
      ]
    },
    {
      "seriesLabels": {
        "__name__": "request_total",
        "group": "test",
        "instance": "192.168.1.198:9464",
        "job": "node",
        "url": "/insert/"
      },
      "exemplars": [
        {
          "labels": {
            "trace_id": "234234234234234234234"
          },
          "value": "1",
          "timestamp": 1617289577.361
        }
      ]
    }
  ]
}

Did I miss something when I configured this data source?

hello Promoteus, what you are looking for is the splunken plugin. please install it and set narrow parameter value to inf.
good luck