JIRA Hipchat integration plugin's REST call fails when called from some other plugin

Question

The JIRA HipChat integration plugin has this REST call which I am unable to invoke successfully from my plugin:

AJS.params.baseURL + "/rest/hipchat/compatibility/1.0/issuepanel/data/"+issueId+".json

This call can give me the parts of the HipChat Room URL I am looking for , and if I make it from REST Browser, or even if I paste this in the address bar of my browser, it still gives me the JSON. But I need to make this call from my plugin , and in that case it always errors out i.e. goes to the error: section of the AJAX call. Please provide your input on this - is there any restrcition in making that REST call from any other plugin?

Code wise, I am basically calling this function I created:

      function getHipChatRoomURL(issueId) {
console.log("Invoking get hipchat room URL");
var hipChatRoomURL = "";
var urlToGetHipchatRoom =  AJS.params.baseURL + "/rest/hipchat/compatibility/1.0/issuepanel/data/"+issueId+".json";
console.log("Attempting to get the hipchat room URL thru this REST Call " + urlToGetHipchatRoom);
AJS.$.ajax({
    url: AJS.params.baseURL + "/rest/hipchat/compatibility/1.0/issuepanel/data/"+issueId+".json",
    dataType: "application/json",
    async:false,
    success: function(response) {
        var apiUrl = response.dedicatedRoom.apiUrl;
        var roomId = response.dedicatedRoom.roomId;
        hipChatRoomURL = apiUrl+"/chat/room/"+roomId;
        hipChatRoomURL = "<a href="+"\'"+ hipChatRoomURL+"\'"+">Join Hipchat Room</a>";
        console.log("Hipchat room URL In AJAX Call is " + hipChatRoomURL);
        return hipChatRoomURL;
    },
    error: function() {
        hipChatRoomURL = "No Hipchat room configured for this issue";
        return hipChatRoomURL;
    }
});
console.log("Get hipchat room URL invoked");
return hipChatRoomURL;

}

And invoking this method like this under AJS.toInit() :

setTimeout(function() {
var issueKey = AJS.Meta.get("issue-key");
AJS.log("ISSUE KEY SENT to find the room URL is " + issueKey)
hipChatRoomURL = getHipChatRoomURL(issueKey);
console.log("Hipchat room URL is " + hipChatRoomURL);
},1000);

But I am seeing that it always executes the error: section of the AJAX call above and returns " No Hipchat room configured for this issue"

Please advise as soon as possible.