I couldn't find anything on this message, I suggest calling into the support department for assistance 1-800-821-2797.
Are you able to provide the error code or message as it appears on the printer. I've tried looking for assertion error and nothing comes back in the search.
Getting an error code after hooking up network cable:
Hard drive has been replaced, unit boots up and operates until the network cable is plug in, then code pops up and unit restarts and continues to restart until network cable removed. Firmware is current.