error-71139-IO communication error

palash

hi,
I am getting this message at teach pendant as soon as I start the controller.
previously I started the robot and checked it in jog mode. then i switched OFF the controller. after restarting again the earth fault breaker fell with breaker from main board.after few more trails the fault was removed on its own. then while trying to enable the robot it showed error 20011-emergency push button pressed. after releasing the em button it is showing the same result.
after this i made I-restart and I am now receiving new error - 71139
thanks for your help
regards,
Palash