Hello! I have the VOIP client installed on my home computer pointed and connected to the newly installed 3CX phone system in my office. Connection is good as I can see all extensions. I'm able to connect to the extensions view Desk Phone Mode, but am unable to connect via Headset mode. I'm also not able to dial out using the Headset mode. Am I missing something? Are there ports which need to be open I can double check and if so which ports? The client works fine on my office computer in both modes. Thanks! So far so good with this product.