Vault auth for OCI giving http_response 401 in error

WHile trying to login to Hashicorp Vault using OCI auth method, getting the following response:

vault login -address=vault_addr -method=oci -path=oci auth_type=instance role=role Error authenticating: Error making API request.

URL: PUT https://vault_addr/v1/auth/oci/login/role Code: 401. Raw Message:

While this is working fine for a setup where the vault is present in the same tenant as the instance, seeing this issue when trying to utilise OCI cross tenant policy. Instance is present in tenant A, and Vault in tenant B. The tenant B has access to list instances in tenant A, ensured this through cli as well.

Could this be happening because vault is unable to use crosstenancy access? Or is there any other issue that could be present?

Start by reproducing the `vault login ... -method=oci` command with the instance in tenant A and Vault in tenant B, then compare it with the same-tenant case and the stated cross-tenancy list policy. Trace the OCI auth login request that returns HTTP 401; done means identifying whether the failure is plugin behavior or tenancy/policy configuration and recording the required correction.

Written by the indexing model from the issue text.