Voice Chat


I use spark 2.5.8 and openfire 3.5.2. Everything is working when I am calling a user via voice chat in xp systems.

But I am unable to connect to the user who is using vista system.
I am getting an error message 'Session closed due to unable to negotiate session.This may be caused by firewall configuration problems’
I have turned off my firewall, and even I am getting the same error messages for users using vista system.

I’m having the same problem. How to solve this problem?