Watcher 2.3 hipchat action not working

[Neha]

Hi,

I've been trying to set up a basic watcher, to send alerts to HipChat, on my v2.3 Elasticsearch cluster. However looking at the watch history tells me it has been consistently failing throwing 400-Bad request errors, as follows:
"actions" : [ {
            "id" : "notify-hipchat",
            "type" : "hipchat",
            "status" : "failure",
            "hipchat" : {
              "account" : "notify-monitoring",
              "sent_messages" : [ {
                "status" : "failure",
                "reason" : "Bad Request",
                "request" : {
                  "host" : "api.hipchat.com",
                  "port" : 443,
                  "scheme" : "https",
                  "method" : "post",
                  "path" : "/v2/room/Room Name/notification",
                  "headers" : {
                    "Content-Type" : "application/json",
                    "Authorization" : "Bearer ValidTokenId"
                  },
                  "body" : "{\n  \"message\" : \"Test ES Cluster status is Green\",\n  \"message_format\" : \"text\",\n  \"color\" : \"green\"\n}"
                },
                "response" : {
                  "status" : 400,
                  "headers" : {
                    "content-length" : [ "0" ],
                    "connection" : [ "Close" ]
                  }
                },
                "room" : "Room Name",
                "message" : {
                  "body" : "Cluster status is Green",
                  "format" : "text",
                  "color" : "green"
                }
              } ]

Using RestConsole, I've verified that the under-question HipChat API calls work otherwise, hence the token is valid.

Mentioned below are the watcher installation details:
{"version":{"number":"2.3.0","build_hash":"0bd7e1459f2eee2318205f2a168bf2d9c6a8dac3","build_timestamp":"2016-03-29T19:51:42Z","build_snapshot":false},"tagline":"You Know, for Alerts & Automation"}

Any help would be deeply appreciated as I am blocked now. Thank you in advance.