User can''t immediately receive the message?

hi all:

some user can’'t see the user who has logined successfully online,also UserA can not receive the message immediately sended by UserB.however,on the console of administration,the administrator can see all users who have logined the system.why? thanks!

the install enviroment show below:

OS:win2000 server

JDK:1.4.2

JIVE Message:2.1

JIVE client:BuddySpace2.5.2pro,JBother-0.8.5.jar

Could you provide more information in order to reproduce the problem such as: presence subscription of each user, steps to follow, etc.?

Thanks,

– Gato