I am setting up my first test deployment of 3CX. I am knowledgeable in IT and networking, but I cannot get a single thing to work. This is a simple setup with local extensions and no external SIP provider. Installed 3CX for Windows version 15.5.3849.1. Configured Firewall Created 3 extensions for Soft Phone use Downloaded the latest Soft Phone Clients I cannot get a single soft phone to register on the LAN. The clients all say that I am not on the latest version, but there are no upgrades left to do.