The answer is a misconfigured OAuth redirect URI for the Salesforce app. Even when your Salesforce credentials are correct and the service is healthy, the Salesforce connector in Power BI relies on OAuth 2.0 to complete the authorization handshake during a scheduled refresh. If the redirect URI registered in the Salesforce connected app does not match Power BI’s exact callback endpoint, the handshake fails, producing the generic 'Unable to connect to the data source' error. On the PL-300 exam, this scenario tests your understanding of how cloud connectors handle authentication behind the scenes—a common trap is assuming the issue is with credentials or network connectivity when the real culprit is a URI mismatch. Remember the mnemonic: “URI must mirror the service’s receiver” to recall that the redirect URI must precisely mirror Power BI’s callback URL for the OAuth flow to succeed.
PL-300 Prepare the data Practice Question
This PL-300 practice question tests your understanding of prepare the data. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are a data analyst for an e-commerce company. You have a Power BI dataset that imports data from a Salesforce source using the Salesforce connector. The dataset is refreshed daily. Recently, the refresh started failing with the error 'Unable to connect to the data source'. You have verified that the Salesforce credentials are correct and that the Salesforce service is healthy. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The OAuth redirect URI for the Salesforce app is not configured correctly.
The Salesforce connector in Power BI uses OAuth 2.0 for authentication. Even if credentials are correct and the Salesforce service is healthy, a misconfigured OAuth redirect URI in the Salesforce connected app prevents Power BI from completing the authorization handshake, causing the 'Unable to connect to the data source' error during refresh. This is a common issue when the redirect URI does not match the Power BI service's callback endpoint.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The OAuth redirect URI for the Salesforce app is not configured correctly.
Why this is correct
Correct. The redirect URI must match the Power BI service URL.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
The privacy levels for the data source are set to 'Private'.
Why it's wrong here
Privacy levels affect data combination, not connectivity.
✗
The Power BI service is not available in the same region as Salesforce.
Why it's wrong here
Region does not affect connectivity.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume credential validity and service health guarantee connectivity, overlooking the OAuth redirect URI configuration which is a frequent misconfiguration in cloud-to-cloud integrations.
Detailed technical explanation
How to think about this question
OAuth 2.0 for Salesforce requires the redirect URI to be exactly 'https://login.microsoftonline.com/common/oauth2/nativeclient' for Power BI cloud refresh. If this URI is missing or incorrect in the Salesforce connected app settings, the authorization code cannot be exchanged for an access token, leading to a connection failure. This is distinct from interactive sign-in, where the redirect URI is handled by the local Power BI Desktop client.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Prepare the data — This question tests Prepare the data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The OAuth redirect URI for the Salesforce app is not configured correctly. — The Salesforce connector in Power BI uses OAuth 2.0 for authentication. Even if credentials are correct and the Salesforce service is healthy, a misconfigured OAuth redirect URI in the Salesforce connected app prevents Power BI from completing the authorization handshake, causing the 'Unable to connect to the data source' error during refresh. This is a common issue when the redirect URI does not match the Power BI service's callback endpoint.
What should I do if I get this PL-300 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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