Thank you for posting this in Microsoft Q&A.
I understand that you are trying to retrieve a private key from Azure Key Vault, but you are getting a null value.
Unfortunately, it is not possible to retrieve a private key from Azure Key Vault. You can only get the public key from Azure Key Vault.
For your reference: https://learn.microsoft.com/en-us/azure/key-vault/keys/quick-create-portal
Hope this helps. Do let us know if you any further queries.
Thanks,
Navya.
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