Hi All I wanna get all contacts from constant contact to salesforce the code is public class constantcontact  { public void conlist() { Http h = new Http();     HttpRequest req = new HttpRequest();   final string username = '54149b86-22eb-496b-a326-132dfa9f3786%rajesh_y';          final string password = 'Dskvap123';         Blob headerValue = Blob.valueOf(username);      String authorizationHeader = 'BASIC ' +EncodingUtil.base64Encode(headerValue);      //String authorizationHeader =username+':'+password;      req.setHeader('Authorization',authorizationHeader);       //req.setHeader('Content-length', '1753' );      req.setHeader('Host','https://api.constantcontact.com/ws/customers//contacts/1');     req.setHeader('Connection','keep-alive');     req.setHeader('Content-Type', 'application/atom+xml');      req.setMethod('GET');       req.setbody('https://api.constantcontact.com/ws/customers/rajesh_y/contacts');       req.setEndpoint('http://api.constantcontact.com/ws/customers/joesflowers/lists');       HttpResponse res = h.send(req);       system.debug('********'+res.getbody());  } }  but i am getting error like. Unauthorized StatusCode=401   whats wrong in the code  All credentials are valid please help me in this area   thank you in advace.  

public class constantcontact 
{
public void conlist()
{
Http h = new Http();
    HttpRequest req = new HttpRequest();
  final string username = '54149b86-22eb-496b-a326-132dfa9f3786%rajesh_y'; 
        final string password = 'Dskvap123';
        Blob headerValue = Blob.valueOf(username);
     String authorizationHeader = 'BASIC ' +EncodingUtil.base64Encode(headerValue);
     //String authorizationHeader =username+':'+password;
     req.setHeader('Authorization',authorizationHeader);
      //req.setHeader('Content-length', '1753' );
     req.setHeader('Host','https://api.constantcontact.com/ws/customers//contacts/1');
    req.setHeader('Connection','keep-alive');
    req.setHeader('Content-Type', 'application/atom+xml');
     req.setMethod('GET');
      req.setbody('https://api.constantcontact.com/ws/customers/rajesh_y/contacts');
      req.setEndpoint('http://api.constantcontact.com/ws/customers/joesflowers/lists');
      HttpResponse res = h.send(req);
      system.debug('********'+res.getbody());

}
}

 Please help me 

thank you in advance