No response from server

Hi,

I am using the below code to remove a contact from roster and some time i am getting exception “No response from server” but there is a valid entry in the roster.

System.Out.println(“REMOVE_ROSTER_ENTRY_ERROR:” + e); this line is printed some times.

try

{

     RosterEntry entry = roster.getEntry(userName);
     if(entry!=null)
     {
              System.Out.println("REMOVING ROSTER ENTRY FOUND WITH NAME:-"+ userName + "(ROSTER_REMOVE)");
              roster.removeEntry(entry);
      }
      else
      {
           System.Out.println("NO ROSTER ENTRY FOUND WITH NAME:-"+ userName + "(ROSTER_REMOVE)");
           return false;
      }

}

catch(XMPPException e)

{

      System.Out.println("REMOVE_ROSTER_ENTRY_ERROR:" + e);
      return false;

}

Where i am doing wrong??

is that a problem with smack API?