bug fix

WebServer/src/code/Home.java

@@ -42,7 +42,7 @@ public class Home implements HttpHandler {
                 response = getKeycloak();
                 strlist.add("text/json");
             }
-            if(!Helper.compareText(response, "fail")){
+            if(response != null && !Helper.compareText(response, "fail")){
                 exchange.getResponseHeaders().put("content-type", strlist);
                 exchange.sendResponseHeaders(200, response.getBytes().length);
                 OutputStream os = exchange.getResponseBody();