HttpClient throws SocketTimeoutException if app was idle

I have a tableview with data loaded from a restful web service. I also have a "Reload" button. Both of them use a HttpClient to get the data from the ws. This usually works great. But.. if the app was idle for some time and I tap on "Reload", the HttpClient always returns SocketTimeoutException. If I try again, it works. So the problem is only the first time after the app was idle. What is the cause of this? How can I solve it?

This issue appears in Android and iOS.

This is the code that makes the request:

var client = Ti.Network.createHTTPClient({
        onload : function(e) {
            if (callback) {
                callback(this.status, true, this.responseText, null);
            }
        },
        onerror : function(e) {
            if (callback) {
                callback(this.status, false, this.responseText, e.error);
            }
        },
        timeout : 5000
    });
    client.open(method, url);
    var loginPass = Ti.Utils.base64encode("username"+':'+ "password");
    client.setRequestHeader('Authorization', 'Basic ' + loginPass);
    client.setRequestHeader("Content-Type", "application/json; charset=utf-8");
    if(OS_IOS) {
        client.send(payload);
    }
    if(OS_ANDROID) {
        client.send(JSON.stringify(payload));
    }