If none of the solutions described by you worked, there is just one more test we could try before send the machine to be repaired by Kevvox.
You will have to open the bottom cover and unscrew the 4 Screws that are holding the T Motor (The motor that moves the tilt table where is the Tray).
After remove the screws, try to turn on the printer and see if the error still happens, if yes, screw it back and try to turn the printer again, It should be resolved in this case.
If the machine still have the issue, we will have to send it to Singapore for repair.