“Must have a local (user) JID set” error

Unable to understand why this error frequently comes on some android devices and app gets crash.

Fatal Exception: java.lang.RuntimeException: Unable to start activity ComponentInfo{.ChatMessageActivity}: java.lang.IllegalArgumentException: Must have a local (user) JID set. Either you didn't configure one or you where not connected at least once
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2493)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2555)
  at android.app.ActivityThread.access$800(ActivityThread.java:176)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1437)
  at android.os.Handler.dispatchMessage(Handler.java:111)
  at android.os.Looper.loop(Looper.java:194)
  at android.app.ActivityThread.main(ActivityThread.java:5576)
  at java.lang.reflect.Method.invoke(Method.java)
  at java.lang.reflect.Method.invoke(Method.java:372)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:956)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:751)
Caused by java.lang.IllegalArgumentException: Must have a local (user) JID set. Either you didn't configure one or you where not connected at least once
  at org.jivesoftware.smack.filter.IQReplyFilter.<init>(IQReplyFilter.java:94)
  at org.jivesoftware.smack.AbstractXMPPConnection.createPacketCollectorAndSend(AbstractXMPPConnection.java:690)
  at org.jivesoftware.smackx.iqlast.LastActivityManager.getLastActivity(LastActivityManager.java:239)
  at com.studyboard.utils.ChatUtil.getLastActivity(ChatUtil.java:674)
  at com.studyboard.ChatMessageActivity.initChat(ChatMessageActivity.java:339)
  at com.studyboard.ChatMessageActivity.onCreate(ChatMessageActivity.java:220)
  at android.app.Activity.performCreate(Activity.java:6005)
  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1111)
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2446)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2555)
  at android.app.ActivityThread.access$800(ActivityThread.java:176)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1437)
  at android.os.Handler.dispatchMessage(Handler.java:111)
  at android.os.Looper.loop(Looper.java:194)
  at android.app.ActivityThread.main(ActivityThread.java:5576)
  at java.lang.reflect.Method.invoke(Method.java)
  at java.lang.reflect.Method.invoke(Method.java:372)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:956)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:751)

Actual error occurs in below function which returns me last status of user for with I am chatting:-

public String getLastActivity(XMPPTCPConnection objXmpptcpConnection, String strUser) {    try {
   LastActivityManager objLastActivityManager = LastActivityManager.getInstanceFor(objXmpptcpConnection);
   LastActivity objLastActivity = null;
   objLastActivity = objLastActivityManager.getLastActivity(strUser + "@" + Constants.HOST);
   System.out.println("MESSAGE:" + objLastActivity.getStatusMessage());
   System.out.println("IDLE TIME::" + objLastActivity.getIdleTime());    return convertTime(objLastActivity.getIdleTime());    } catch (SmackException.NoResponseException e) {
  e.printStackTrace();
   return "Offline";
   } catch (XMPPException.XMPPErrorException e) {
  e.printStackTrace();
   return "Offline";
   } catch (SmackException.NotConnectedException e) {
  e.printStackTrace();
   return "Offline";
   }    }

I have get error on line number 6 in above function.

Please suggest solution.Thanks in advacne.