I have been experiencing a strange problem lately , all of my outlook users get disconnected and goes to "Trying to connect"status come back online after i restart cas servers. meanwhile owa & mobile users are able to use their emails without any disconnection. I have been searching for the logs but i haven't found any solution yet . Please help me to identify the issue. server address is pointing to Windows NLB interface CAS servers.
also i have checked port 443 is not blocked by Firewall.
PS:- I'm using Microsoft exchange 2013 Enterprise ,2 cas servers & 2 mbx servers on windows server 2012