Hi, I have installed the 3CX 11 with SP3 on my lab in one of the virtual machine, and have an Exchange Server 2013 installed on two virtual machines on Hyperv 2012. One server with Exchange CAS 2013 and other for MB 2013. Unified messaging is enabled. When I try to enable the integration option in 3CX (Settings >Advanced > Exchange 2007/2010). But the option " Use exchange server for voice mail" is disabled state and I cannot tick the check box to enable the same. Please let me know how to enable this?