FabCores, (and all new machines) conduct a start up test.
This means when you first power on your machine you will need to open and close the door.
This allows the controller inside the machine verify the interlocks are functioning and have not been defeated by a previous user.
You may need to wait a moment for the controller to boot. Normally when the machine has homed is enough time. After which open and close the door and they will turn green 
Also remember the chiller is interlocked too. So if you turn your chiller off or its not on when you power on the machine your interlocks will never go ‘green’.
If you turn your chiller off but not the FabCore and come back to turn the chiller on you will need to open and close the door again so it can check everything is working again.