Can anyone advise how they handle failover for 3CX phone systems, for the Internet connection? My cunning plan, when a customer had a line fault that caused their ADSL to drop to put a 4G connection in place so that the phone system could still work via 4G, and the desk phones could reach the PC. That way ONLY the phone system data would work across the 4G and the kids/users trying to use Netflix/YouTube wouldn't kill the limited amount of data on the 4G service. However on deploying this and getting access back to the PC with 3CX on it I found I couldn't reach the web interface (locally) and noted that the ngix web service had stopped. I could start it, but within seconds it would stop with warning event log saying the service had stopped (code 2?). I then thought the phone system had an issue at the same time as the ADSL service and proceeded to perform all kinds of troubleshooting on the 3CX system, to the point where I've uninstalled and reinstalled 3CX a LOT of times. Now I'm stuck that I'm getting a generic "licence activation failed" regarding an adaptor issue, but having completed fresh installs, etc, it's not related to restoring a backup or installing fresh, etc. So: root cause: primary internet not available, so attempted to setup a local 4G connection secondary cause: ngix doesn't seem to like having a cabled (but not internet active) connection and a 4G connection running at the same time Any hints would be great. I think for the moment I may just need to setup the 4G attached to the router in some way for failover purposes, once I actually manage to get the phone system reinstalled.