issue #264 fixed

android/Pictogram/commonlibrary/src/main/java/com/yottacode/pictogram/net/NetService.java

@@ -185,6 +185,7 @@ public class NetService implements Runnable, RestapiWrapper.iSilentLogin {
                         if (PCBcontext.is_user_logged()) {
                             if (restfullSynchroTimming > 0 && (now>= nextRestfullSynchro)) {
                                 Log.i(LOG_TAG, "Vocabulary request.");
+                                PCBcontext.getRoom().connect();
                                 PCBcontext.getVocabulary().synchronize();
                                 synchronizeStudentAttributes();
                                 nextSynchro(now+restfullSynchroTimming);