Comment 1 for bug 1844092

The token in the relation data is a one-shot token which is used to request a secret ID from Vault which is then saved and used for future requests. This is failing on the retrieve_secret_id call; the most likely reason why this would fail is if it was called more than once, possibly due to a previous hook error.

Can you check the logs and confirm whether this failure was the first error in the logs? Also, can you see if the secret_id already has a value:

juju run --unit kubernetes-master/0 -- chlp unitdata get layer.vault-kv.secret_id