[Bug] IMDS v2 fails to detect source correctly when identity not found

[gladjohn]

Library version used

msal mTLS pop preview

Issue Description:

During Managed Identity source detection, MSAL sends the initial platform-metadata GET (cred-api-version=2.0) with a client_id selector for UAMI. If that UAMI isn’t assigned to the VM, IMDS returns “Identity not assigned to VM.” MSAL misclassifies this as “IMDSv2 not available,” exits the IMDSv2 path, and throws MsalClientException.

Expected behavior

should detect MSI v2 source when available.

Identity provider

Microsoft Entra ID (Work and School accounts and Personal Microsoft accounts)

Regression

No response

Solution and workarounds

Fix: Reclassify this as a UAMI configuration error rather than endpoint unavailability.

[Robbie-Microsoft]

What is the status of the error sent back from Imds? What is the exact string? Can you paste the whole error object here?

[Robbie-Microsoft]

Would you like to see the new UAMI configuration error during both probe mode and regular ImdsV2 flow? I think during probe mode, we should just log the new error, and during regular flow we should throw the new error.