How to get twitter screenname on mule - twitter

Question

I want to send a tweet with mule but I get a NullPointerException on the #[payload.user.screenName], how can I get the screenName??and all the other ways neither worked
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:twitter="http://www.mulesoft.org/schema/mule/twitter" xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking" xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
xmlns:spring="http://www.springframework.org/schema/beans" version="EE-3.6.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
http://www.mulesoft.org/schema/mule/ee/tracking http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd
http://www.mulesoft.org/schema/mule/twitter http://www.mulesoft.org/schema/mule/twitter/current/mule-twitter.xsd">
<http:request-config name="HTTP_Request_Configuration" host="api.openweathermap.org" port="80" basePath="data/2.5/weather?q=Cadiz,es&APPID=mykey" doc:name="HTTP Request Configuration"/>
<twitter:config name="Twitter" accessKey="${twitter.accessKey}" accessSecret="${twitter.accessSecret}" consumerKey="${twitter.consumerKey}" consumerSecret="${twitter.consumerSecret}" doc:name="Twitter"/>
<flow name="pruebaFlow">
<poll doc:name="Poll">
<fixed-frequency-scheduler frequency="10000"/>
<http:request config-ref="HTTP_Request_Configuration" path="/" method="GET" doc:name="HTTP"/>
</poll>
<byte-array-to-string-transformer doc:name="Byte Array to String"/>
<echo-component doc:name="Echo"/>
<twitter:show-user config-ref="Twitter" doc:name="Twitter"/>
<twitter:send-direct-message-by-screen-name config-ref="Twitter" message="#[header.INBOUND:message]" screenName="#[payload.user.screenName]" doc:name="Twitter"/>
</flow>
</mule>
And this is the stracktrace
Exception stack is:
1. null (java.lang.NullPointerException)
org.mule.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer:363 (null)
2. [Error: null pointer: payload.user.screenName]
[Near : {... payload.user.screenName ....}]
^
[Line: 1, Column: 1] (org.mule.mvel2.PropertyAccessException)
org.mule.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer:434 (http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/mvel2/PropertyAccessException.html)
3. Execution of the expression "payload.user.screenName" failed. (org.mule.api.expression.ExpressionRuntimeException)
org.mule.el.mvel.MVELExpressionLanguage:202 (http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/expression/ExpressionRuntimeException.html)
4. Failed to invoke sendDirectMessageByScreenName. Message payload is of type: UserJSONImpl (org.mule.api.MessagingException)
org.mule.devkit.processor.DevkitBasedMessageProcessor:128 (http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/MessagingException.html)
--------------------------------------------------------------------------------
Root Exception stack trace:
java.lang.NullPointerException
at org.mule.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:363)
at org.mule.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:140)
at org.mule.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
+ 3 more (set debug level logging or '-Dmule.verbose.exceptions=true' for everything)
and now I have a new error this
RROR 2015-03-31 22:36:55,067 [[prueba].HTTP_Listener_Configuration.worker.01] org.mule.retry.notifiers.ConnectNotifier: Failed to connect/reconnect: Work Descriptor. Root Exception was: 401 response received, but no WWW-Authenticate header was present. Type: class java.lang.IllegalStateException
ERROR 2015-03-31 22:36:55,075 [[prueba].HTTP_Listener_Configuration.worker.01] org.mule.exception.DefaultMessagingExceptionStrategy:
********************************************************************************
Message : Error sending HTTP request. Message payload is of type: MuleHttpClient$1
Code : MULE_ERROR-29999
--------------------------------------------------------------------------------
Exception stack is:
1. 401 response received, but no WWW-Authenticate header was present (java.lang.IllegalStateException)
com.ning.http.client.providers.grizzly.GrizzlyAsyncHttpProvider$AsyncHttpClientEventFilter$AuthorizationHandler:1623 (null)
2. java.lang.IllegalStateException: 401 response received, but no WWW-Authenticate header was present (java.util.concurrent.ExecutionException)
org.glassfish.grizzly.impl.SafeFutureImpl$Sync:363 (null)
3. java.util.concurrent.ExecutionException: java.lang.IllegalStateException: 401 response received, but no WWW-Authenticate header was present (java.io.IOException)
org.mule.module.http.internal.request.grizzly.GrizzlyHttpClient:282 (null)
4. Error sending HTTP request. Message payload is of type: MuleHttpClient$1 (org.mule.api.MessagingException)
org.mule.module.http.internal.request.DefaultHttpRequester:190 (http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/MessagingException.html)
--------------------------------------------------------------------------------
Root Exception stack trace:
java.lang.IllegalStateException: 401 response received, but no WWW-Authenticate header was present
at com.ning.http.client.providers.grizzly.GrizzlyAsyncHttpProvider$AsyncHttpClientEventFilter$AuthorizationHandler.handleStatus(GrizzlyAsyncHttpProvider.java:1623)
at com.ning.http.client.providers.grizzly.GrizzlyAsyncHttpProvider$AsyncHttpClientEventFilter.onHttpHeadersParsed(GrizzlyAsyncHttpProvider.java:1422)
at org.glassfish.grizzly.http.HttpCodecFilter.decodeHttpPacketFromBytes(HttpCodecFilter.java:664)
+ 3 more (set debug level logging or '-Dmule.verbose.exceptions=true' for everything)
********************************************************************************