Solution
To resolve this problem, turn off the system and then power up the system following the instructions as listed in the Connecting the RM-26999 to a DAQ Multifunction I/O module
Failing to follow the instructions as directed may result in the RM-26999 not seeing the expected voltage from the data acquisition device or the 24V power supply. If the protection circuitry on the 24V power supply input trips, the RM-26999 will go into a protection mode and turn off the blue status LED. You must cycle power on the RM-26999 and follow in order to reset this protection mode. Then follow the provided steps as mention in the user manual.
In a similar manner, connecting your current sensors to the RM-26999 while it is already powered on might also cause the protection circuit on the 24V power supply input lines to trip and also turn off the blue status LED. The RM-26999 User Manual also instructs you to power off your system before connecting your current and voltage sensors. Follow the instructions as listed in the Connecting Voltage and Current Signals in the user manual.