I am not able to chat between two contacts

Hello I have created 2 users i.e user1 and user2

Then i have added user1 to roaster of user2 and user2 to roaster of user1 with following way

RosterItemEntity rosterItemEntity = new RosterItemEntity("user1@testdomain.com", "user1", 3);

  List<String> groups = new ArrayList<String>();

  groups.add("Supporter");

  rosterItemEntity.setGroups(groups);

  restApiClient.addRosterEntry("user2", rosterItemEntity);

RosterItemEntity rosterItemEntity = new RosterItemEntity("user2@testdomain.com", "user2", 3);

  List<String> groups = new ArrayList<String>();

  groups.add("Supporter");

  rosterItemEntity.setGroups(groups);

  restApiClient.addRosterEntry("user1", rosterItemEntity);

Then i login with user1 in one  client and login with user2 in second client

user1 showing one contact user2 similarly user2 shows one contact user1

But when i sent message from user1 to user2 or user2 to user1. messages are not delivered to each other