Error 500 is common on firmware versions prior to V6. 

Typically it happens when the user tries to cancel a job while the printer is running or paused or if a user tries to delete a job from the machine memory.  

On earlier version of the mcor firmware (4-2.2 and earlier) you can  recover this by shutting down the printer and re-starting it.  (Note: Always shut down the machine using the Orange setup menu for safety)

On V6 firmware printers all job cancellation and job deleting can be carried out without errors.

Error 500 can also occur while deleting jobs from the printer memory due to errors on the controller SD card. These errors are generally caused when printers power is cut without stopping the controller first. This error requires a remote support session with Cleangreen3d support or the SD card be simply removed and repaired in a Windows machine.  

On V6 firmware we have added a controller shut down item to the setup/power menu on the printer.