Spark Clients loosing connection

First off I need to thanks every for creating a great community and an awesome product.

Heres the issue I have spark users that are loosing connection to the wifi server. On the client side they will get a message saying they have been disconnected and ask them if they want to reconnect. I have looked over my firewall and wifi logs and I can’t see any reason server side why they loose connection. This even happens to a couple users on the same LAN as the wifi server. I was wondering if there is a setting co change the max timeout for connected users. Or if this is even the right direction to look. We are running wifi 2.6.2 and its on 2003 server web edition and auth. comes from active directory. I would really appreciate some help on where I need to start looking to find the cause of the problem.