Fixed geo-dashoard authorization issue

components/extensions/cdmf-transport-adapters/output/org.wso2.carbon.device.mgt.output.adapter.websocket/src/main/java/org/wso2/carbon/device/mgt/output/adapter/websocket/authorization/DeviceAuthorizer.java

@@ -81,7 +81,7 @@ public class DeviceAuthorizer implements Authorizer {
     }
 
     @Override
-    public boolean isAuthorized(AuthenticationInfo authenticationInfo, Session session, String stream) {
+    public  synchronized boolean isAuthorized(AuthenticationInfo authenticationInfo, Session session, String stream) {
         WebSocketSessionRequest webSocketSessionRequest = new WebSocketSessionRequest(session);
         Map<String, String> queryParams = webSocketSessionRequest.getQueryParamValuePairs();
         String deviceId = queryParams.get(DEVICE_ID);