Did you use these?
https://www.usa.canon.com/internet/portal/us/home/support/details/printers/support-laser-printers-imageclass/imageclass-mf3240/!ut/p/z1/jY_dCoJAEIWfpQdYdtCyvFw10XALpcz2JpZQW_BnWa2Lnr4tiojImquZwzcz52CGM8wafhYl70Xb8ErPO2btaRzMgtCFaOUbcyB0nUbUDE1ILLy9A_ClCGD2z_4AwIbPL3490AkMRV1aYiZ5f0SiKVqcSSWaPlcdzrqTlK3qUcW7XKGnjkTNy_ygRY28elQXpjEG7Zq9_4XEngKxPCuwlw6E8eQDSJ2xBmzPNQ3_5v0BDEST9Sa7RI4dCjK6AiBL6iM!/DriversAndSoftware?tab=drivers_downloads