guix deploy: Failed to read private key

[Kitty-Cricket Piapiac]

Hello Guix,

I am relatively new to this package manager & system distribution. I am 
really struggling to get `guix deploy` working. I have a simple 
`deploy.scm` that looks something like this.

  $ cat deploy.scm
  (define %os (operating-system ...))

  (define %ip "<ip>")
  (define %key "<host-key>")

  (list
    (machine
      (operating-system %os)
      (environment managed-host-environment-type)
      (configuration (machine-ssh-configuration
                       (host-name %ip)
                       (host-key %key)
                       (identity "id_ed25519")))))

When I try and run `guix deploy deploy.scm` as a regular user, I get the 
following error:

  $ guix deploy deploy.scm
  The following 1 machine will be deployed:
    <name>

  guix deploy: deploying to <name>
  guix deploy: error: failed to deploy <name>: SSH authentication 
failed for '<ip>': Failed to read private key: /home/kitty/.ssh/id_ed25519

At first I thought there may be a permissions issue, but the private key 
is there, and with seemingly the right permissions,

  $ ll /home/kitty/.ssh/id_ed25519
  -rw------- 1 kitty users 464 Feb 13 00:03 id_ed25519

and ssh-ing into the machine normally works fine,

  $ ssh root@<ip>
  Enter passphrase for key '/home/kitty/.ssh/id_ed25519':
  Last login: Mon Feb 13 17:24:54
  root@<name> ~#

so I'm not really sure what could be causing this, and I'm not sure what 
to do now to troubleshoot. Anybody run into this before, or any ideas?

Thanks,
Kitty-Cricket Piapiac