1.I still receive the error message "Replace Drum", "Drum End Soon", "Drum Near End", or "Drum Stop" after I replace the drum unit with a new one.

2.Check Connection

3.The scanned data is attached to an E-mail application which I do not use regularly, or the error message indicating no default E-mail application is registered on my computer (CC4-121-[error code]) when trying to scan a document directly into my E-mail application using ControlCenter4 or the SCAN key on my Brother machine.

4.Replace Toner

5.I just replaced the toner cartridge and the LCD continues to display the message "Toner Low" / "Replace Toner" / "Toner Ended" or the Toner LED is still on or flashing.