TWRP decrypt password
It's a issue with TWRP and the ROM you are using. TWRP is able to decrypt till Android 8.0 but if you're using a ROM above it you'll get this error and after flashing your data partition to ext4 it will let you use that space till ROM boot up and encrypt again. There isn't a solution yet. TWRP releases updated version 3.2.3_1 for few devices only which has this bug fixes.