Device to use with cryptsetup Buster encrypted lvm

[john doe <johndoe65534@mail.com>]

Debians,

I just installed Debian Buster with encrypted LVM.

In my fstab file, I have:
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/dev/mapper/try02--vg-root /               ext4    errors=remount-ro 0
     1

I can't figure out what device I should pass to cryptsetup to avoid the
below error:

$ cryptsetup -v luksAddKey /dev/mapper/try02--vg-root /etc/keys/root.key
--key-slot=1
Device /dev/mapper/try02--vg-root doesn't exist or access denied.
Command failed with code -4 (wrong device or file specified).


How can I know what device cryptsetupt will accept?

--
John Doe