This problem is already reported, but still i cant find any solution, in my company there is 250+ users and most of time 150+ user connected. Also IM gateway is used, no LDAP and no AD. Using Mysql 4.0.24, JDK 1.4.2_08-b02, Open fire 3.5.2 running on Sparc solaris 10 behinde the load balancer(hardware device). I was running perfectly then i changed the server name and load new self signed certificate(first i use im.abc.com and then i use im.abcinc.com). I think after that it disconnected frequently i also observe not all discoonnected bur some of them.
i cant find any thing unusallal in log file but i attached the log files that might help you find the problem or please let me know if you need any thing else.