I am running Windows 8.1 Pro. When my 3CX Phone registers, it allows me to make/receive call, however, after that call has finished, I can no longer make calls from the phone. When pressing the call button, it immediately goes back to the keypad as if I had pressed the cancel button. It can still receive calls though :S Also, I get no audio through the 3cxphone from the other end, I dont have a mic connected so cant test if the other end can here me, i can send tones from the 3cx to the other phone though, so i assume so. The only way to fix this is to close the phone down and start it again, or switch it to cti mode then back to 3cx. I have an iPhone on the network with 3cx phone that is set up the exact same way as the windows phone, and the iphone one works fine. Any ideas?