Prepare the data →mediumMultiple ChoiceObjective-mapped

PL-300 Prepare the data Practice Question

Exhibit

{
  "credentials": [
    {
      "datasource": "AzureBlob",
      "credentialType": "Anonymous"
    },
    {
      "datasource": "SqlServer",
      "credentialType": "Basic",
      "username": "bi_user",
      "password": "EncryptedPassword"
    }
  ]
}

Refer to the exhibit. You are reviewing a Power BI data source credential configuration. The Azure Blob Storage data source uses 'Anonymous' credentials. However, the refresh fails with an error indicating that the blob container is private and requires authentication. Which change should you make?

⚠ Common exam trap

Watch out — candidates often confuse 'Anonymous' with a valid credential type for private containers, or incorrectly assume that 'Basic' authentication is equivalent to providing a username and password for Azure Storage.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Change credential type to 'Account Key' and provide the storage account key.

Azure Blob Storage containers that are private require authentication. The 'Account Key' credential type in Power BI uses the storage account key to authenticate via the Azure Storage REST API, which is the correct method for accessing private blob containers. Anonymous access only works when the container is configured for public access.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Change credential type to 'Service Principal' and provide the app ID and secret.
Why it's wrong here
A Service Principal credential authenticates to Azure Blob Storage via Microsoft Entra ID, but the error states the container is private and requires authentication, not that the current identity lacks permissions. The anonymous credential is already failing because the container denies unauthenticated access, so switching to a Service Principal would provide authentication, but the question’s scenario does not specify that a Service Principal has been granted access to the container. It is tempting because Service Principals are commonly used for automated, non-interactive access to Azure resources, and would be correct if the container’s access control list (ACL) or Azure RBAC had already assigned the Service Principal the necessary Storage Blob Data Reader role.
✓
Change credential type to 'Account Key' and provide the storage account key.
Why this is correct
When an Azure Blob Storage container is private, Power BI's anonymous (public) access is rejected, so you must authenticate with a credential the storage service actually recognizes. The Azure Blob connector in Power BI supports Account Key authentication as the straightforward shared-key method: supplying the storage account key authorizes your request as the account owner. This grants full access to the container and resolves the 'container is private' error without needing to configure Azure RBAC roles. Use the key from the storage account's Access keys blade in the Azure portal.
✗
Change credential type to 'Basic' and provide the storage account name and key.
Why it's wrong here
Basic authentication sends a simple username/password payload that Azure Blob Storage does not accept; the Basic credential type is designed for SQL Server, MySQL, or other data sources that support user/password login challenges. Even if you supply the storage account name and the account key in the username and password fields, Power BI will not translate that into the Shared Key or SAS authorization scheme Azure Blob requires. For Azure Blob, Power BI expects Account Key, SAS, or Entra ID-based credential types, so selecting Basic will fail.
✗
Change credential type to 'Windows' for the Azure Blob datasource.
Why it's wrong here
Windows authentication relies on NTLM or Kerberos against a domain-joined environment, which is meaningful only for on-premises sources like SQL Server or file shares. Azure Blob Storage is a cloud service with no concept of Windows domain credentials, so Power BI will not even offer or accept Windows as a valid credential type for that data source. Even if it did, the storage service cannot verify a Windows user, making this option completely incompatible with the error at hand.

Quick reference

Azure Blob Storage Tier Comparison

Tier	Storage Cost	Retrieval Cost	Latency	Use Case
Hot	Highest	Lowest	Immediate	Active data, frequent reads
Cool	Lower	Higher	Immediate	Data accessed < once / month
Cold	Lower still	Higher	Immediate	Data accessed < once / quarter
Archive	Lowest	Highest + rehydration delay	Hours	Long-term compliance retention

Go deeper

PL-300 Prepare the data Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

Azure Blob Storage Tier Comparison

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