Am getting the following error in POST http method.

Error: CSRF token validation failed and System.HttpResponse[Status=Forbidden, StatusCode=403]"|0x43de18c1

I have two http request, 1. GET and 2. POST. Please review my code below and let me know where am missing.

GET:

    Http h = new Http();
    // Instantiate a new HTTP request, specify the method (GET) as well as the endpoint
    HttpRequest req = new HttpRequest();
    req.setHeader('Content-Type', 'application/atom+xml');    
    req.setHeader('x-csrf-token', 'fetch');
    req.setHeader('Authorization', 'BASIC ' + EncodingUtil.base64Encode(Blob.valueOf('username:pasword')));
    req.setMethod('GET');
    req.setEndpoint(url1);
    HttpResponse res = h.send(req);

POST: Using the above response and passing the CSRF token to my POST method,

        req.setHeader('Content-Type', 'application/atom+xml');
        req.setHeader('X-CSRF-Token',maptoken.get('x-csrf-token'));   
        req.setHeader('Authorization', 'BASIC ' + EncodingUtil.base64Encode(Blob.valueOf('username:pasword')));
        req.setMethod('POST');
        req.setEndpoint(url2);     
        req.setBody('xml hard coded');
        HttpResponse ires = h.send(req);