Accessing RSS feed URL issue

Hi everybody,
I want to configure outlook to feed announcement RSS from webcenter spaces but when I want to access to the RSS feed URL I get this exception:

Error 500--Internal Server Error

java.lang.NullPointerException at oracle.webcenter.rss.servlet.RSSServlet.doGet(RSSServlet.java:93) at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:300) at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at oracle.wcps.client.PersonalizationFilter.doFilter(PersonalizationFilter.java:75) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at oracle.webcenter.content.integration.servlets.ContentServletFilter.doFilter(ContentServletFilter.java:168) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at oracle.adf.share.http.ServletADFFilter.doFilter(ServletADFFilter.java:62) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at oracle.security.jps.ee.http.JpsAbsFilter$1.run(JpsAbsFilter.java:111) at java.security.AccessController.doPrivileged(Native Method) at oracle.security.jps.util.JpsSubject.doAsPrivileged(JpsSubject.java:313) at oracle.security.jps.ee.util.JpsPlatformUtil.runJaasMode(JpsPlatformUtil.java:413) at oracle.security.jps.ee.http.JpsAbsFilter.runJaasMode(JpsAbsFilter.java:94) at oracle.security.jps.ee.http.JpsAbsFilter.doFilter(JpsAbsFilter.java:161) at oracle.security.jps.ee.http.JpsFilter.doFilter(JpsFilter.java:71) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at oracle.dms.servlet.DMSServletFilter.doFilter(DMSServletFilter.java:136) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3715) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3681) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2277) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2183) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1454) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209) at weblogic.work.ExecuteThread.run(ExecuteThread.java:178)