You need to look inside the Ctx, if you see a card called IES you need to hold down the shutdown button for 7 + seconds until the orange shutdown light is lit then press the power button until bth lights go out, it is now safe to power down the Ctx, as far as i am aware teleco's, gvmu's and lvmu's are ok if you just power down the Ctx then power the Ctx back up and try again.
Sometimes the port locks up but you can still ping the nic.

Live Long and Prosper My Friends