Registration failed. Press OK or Go and try again. If the message is still displayed, do one of the following:

• Press and hold down (Power On/Off) to turn off the machine. Wait a few seconds, then turn it on again.
  Perform the automatic color registration using the control panel. (Click here to see how to adjust the print position of each color.)
• Put in a new belt unit. (Click here to see the details of how to replace the belt unit.)

If the issue continues, call your dealer or Brother Customer Service.