Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h7/STM32H723/FDCAN1/FDCAN_TXBCF#0x0
FDCAN Tx Buffer Cancellation Finished Register
Cancellation Finished
https://github.com/modm-io/cmsis-svd-stm32