I just installed 3CX and am having an issue with the 3CXPhone for Windows client, version 15.5.8801.3. When used from a remote location, the client connects properly, shows on-hook, displays presence information etc, and can receive and initiate calls. However, there is no outbound audio from the client during calls. Inbound audio works fine (unless the other end is also a remote 3CXPhone for Windows client - they don't send audio either). Interestingly, if the remote location is connected via a VPN tunnel to the physical location hosting the PBX, audio works just fine in both directions. Note that even if traveling over the VPN the client is NOT on the same network as the PBX. AND, just to make things interesting the Free 3CX Softphone, ver 6.0.26523.0, works just fine with or without the VPN tunnel to the office from the same remote workstation. Any thoughts on what may be happening here? Thanks.