I'm trying to fetch joined member list from particular group based on room JID, there are couple of method exists, mentioned below: 
- MultiUserChat.getMembers();  It return 
XMPPError: forbidden - auth - MultiUserChat.getOccupants(); It return self info only
 - MultiUserChat.getParticipants(); It return
XMPPError: forbidden - auth 
But none of working getting exception XMPPError: forbidden - auth, it seem there is something issue with privacy,which I'm not able to figure out. 
Note: JID the name of the room in the form "roomName@service"