ZFS error for load-key

I've tried everything I know until I'm exhausted. Please, if you can help me, I need to access my project stored on my hard drive. The command I used:

sudo zfs load-key rpool/ROOT/ubuntu_uy913x

And the error message I received:

Key load error: Keys must be loaded for encryption root of 'rpool/ROOT/ubuntu_uy913x' (rpool).