Why does custom TWRP recovery crash?

Question

Android

I have xiaomi redmi note 6 pro. I unlocked the bootloader and flashed TWRP recovery. But when you reboot and turn on the phone, it requires a password to unlock the android (or something else, I don’t remember). Passwords from the phone or accounts are not suitable. I was helped by resetting the settings (through the recovery). But when I turned off the phone and booted into the recovery, the stock recovery loaded, and what I was flashing disappeared. What to do?