Using the latest firmware.
Downloaded firmware via RobotC, and also with the Firmware Upgrade Utility.
Using 2.0 keys; keys are ok as I can pair other cortex-transmitter pair using these two keys.
Cortex: Game - fast green blink, Vexnet - off, Robot - slow green blink
Transmitter: Robot - slow green blink, Vexnet - green on, Joystick - red when power off, green when power on
Not sure what else to try.