I just added new Exchange 2010 CAS/HUB servers. They redirect users that have 2007 mailboxes to my 2007 CAS servers but you can only stay logged in for a couple seconds and users keep getting booted out. I switched DNS and URLS back to see if things worked the way they used to. Things are still not working right. I can log in but cant stay logged in without getting redirected to the log in screen.