Issue with implement proxy in elasticsearch/kibana

[lgriger (Ladislav Griger)]

elasticsearch config
xpack.http.proxy.host: http://
xpack.http.proxy.port: 8080
xpack.http.proxy.scheme:http

kibana config
xpack.fleet.registryProxyUrl: http://<user:password@url>
xpack.actions.proxyUrl: http://<user:password@url>
xpack.actions.proxyHeaders:
Proxy-Authorization: "Basic "

watcher config:

{
  "trigger": {
    "schedule": {
      "interval": "1m"
    }
  },
  "input": {
    "search": {
      "request": {
        "search_type": "query_then_fetch",
        "indices": [
          "*"
        ],
        "rest_total_hits_as_int": true,
        "body": {
          "size": 0,
          "query": {
            "match_all": {}
          }
        }
      }
    }
  },
  "condition": {
    "compare": {
      "ctx.payload.hits.total": {
        "gte": 10
      }
    }
  },
  "actions": {
    "my_action_test_proxy": {
      "webhook": {
        "scheme": "https",
        "host": "monlytest.eu",
        "port": 443,
        "method": "post",
        "path": "/monly-backend/v1/status",
        "params": {},
        "headers": {
          "Content-Type": "text/html"
        }
      }
    }
  }
}

watcher output:
"condition": { "type": "compare", "status": "success", "met": true, "compare": { "resolved_values": { "ctx.payload.hits.total": 1004 } } }, "actions": [ { "id": "my_action_test_proxy", "type": "webhook", "status": "failure", "error": { "root_cause": [ { "type": "unknown_host_exception", "reason": ": Name or service not known" } ], "type": "unknown_host_exception", "reason": ": Name or service not known" } } ] }, "messages": }