diff --git a/src/main/java/org/gcube/portlets/user/joinvre/server/JoinServiceImpl.java b/src/main/java/org/gcube/portlets/user/joinvre/server/JoinServiceImpl.java
index 16e835f..23dfadf 100644
--- a/src/main/java/org/gcube/portlets/user/joinvre/server/JoinServiceImpl.java
+++ b/src/main/java/org/gcube/portlets/user/joinvre/server/JoinServiceImpl.java
@@ -39,6 +39,7 @@ import org.gcube.vomanagement.usermanagement.model.MembershipRequestStatus;
 import org.gcube.vomanagement.usermanagement.model.VirtualGroup;
 
 import com.google.gwt.user.server.rpc.RemoteServiceServlet;
+import com.liferay.portal.kernel.cache.CacheRegistryUtil;
 import com.liferay.portal.kernel.exception.PortalException;
 import com.liferay.portal.kernel.exception.SystemException;
 import com.liferay.portal.kernel.log.Log;
@@ -225,6 +226,7 @@ public class JoinServiceImpl extends RemoteServiceServlet implements JoinService
 					if (session.getUsername().compareTo(TEST_USER) != 0) {
 						GCubeUser currUser = new LiferayUserManager().getUserByUsername(session.getUsername());
 						//check if the user belongs to it
+						CacheRegistryUtil.clear();
 						if (gm.listGroupsByUser(currUser.getUserId()).contains(vreOrganization)) {
 							toAdd.setUserBelonging(UserBelonging.BELONGING);
 						}
@@ -351,6 +353,7 @@ public class JoinServiceImpl extends RemoteServiceServlet implements JoinService
 	 * @throws UserManagementSystemException 
 	 */
 	private static boolean checkPending(String screenName, long groupId) throws UserManagementSystemException, GroupRetrievalFault, UserRetrievalFault {
+		CacheRegistryUtil.clear();
 		UserManager um = new LiferayUserManager();
 		List<GCubeMembershipRequest> requests  = um.listMembershipRequestsByGroup(groupId);
 		for (GCubeMembershipRequest r : requests) {