The COM ports are defined and the communications works great but when the ENC is rebooted it is unable to start up the serial port (COM3), it says “COM3 is not a valid port”. However, once the station is running COM3 can be typed in the drivers properties and it works fine.
ENC, G3, Niagara
The station was loading the "Drivers" before the "Services". The Services must come first to prepare the ports before the Drivers are loaded.
Open the running station in Workbench, right click on Config and pull down to "Reorder". Change the order to load the Services first, save the change and reboot the station.