The answer is that the database server is not accessible or credentials are missing. This is correct because Power Query Editor runs queries against a cached data preview, not a live connection, so a successful preview does not guarantee the actual data load will succeed. When you click Close & Apply, Power BI attempts a full live connection to the Azure SQL database to refresh the dataset, and if the server is unreachable, the credentials have expired, or the connection string is invalid, the load will fail despite the earlier preview working. On the PL-300 exam, this scenario tests your understanding of the difference between the editor’s cached environment and the live refresh process—a common trap where candidates assume a successful preview means the load will also succeed. Remember the key distinction: preview uses cache, load requires live. A helpful memory tip is “Preview is a peek, load needs a link.”
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.
Exhibit
Refer to the exhibit.
// Power Query M code snippet
let
Source = Sql.Database("myserver.database.windows.net", "SalesDB"),
dbo_Orders = Source{[Schema="dbo",Item="Orders"]}[Data],
#"Filtered Rows" = Table.SelectRows(dbo_Orders, each [OrderDate] > #date(2024,6,1))
#"Removed Columns" = Table.RemoveColumns(#"Filtered Rows",{"OrderDetails"})
in
#"Removed Columns"
You are reviewing the M query above. The query connects to an Azure SQL database and filters orders after June 1, 2024. The query runs successfully in Power Query Editor, but when you close and apply, the data load fails. 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.
Refer to the exhibit.
// Power Query M code snippet
let
Source = Sql.Database("myserver.database.windows.net", "SalesDB"),
dbo_Orders = Source{[Schema="dbo",Item="Orders"]}[Data],
#"Filtered Rows" = Table.SelectRows(dbo_Orders, each [OrderDate] > #date(2024,6,1))
#"Removed Columns" = Table.RemoveColumns(#"Filtered Rows",{"OrderDetails"})
in
#"Removed Columns"
A
The date filter syntax is invalid.
Why wrong: The syntax is correct.
B
The query has a syntax error in the let expression.
Why wrong: The query runs in Editor, so syntax is fine.
C
The database server is not accessible or credentials are missing.
Network or authentication issues can cause load failure.
D
The column 'OrderDetails' does not exist.
Why wrong: If it didn't exist, the Editor would error.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The database server is not accessible or credentials are missing.
The query runs successfully in Power Query Editor but fails during 'Close & Apply' because the editor uses a cached data preview, while the actual load requires a live connection to the Azure SQL database. The most likely cause is that the database server is inaccessible or the credentials are missing or expired at load time, which is a common connectivity issue in Power BI.
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 date filter syntax is invalid.
Why it's wrong here
The syntax is correct.
✗
The query has a syntax error in the let expression.
Why it's wrong here
The query runs in Editor, so syntax is fine.
✓
The database server is not accessible or credentials are missing.
Why this is correct
Network or authentication issues can cause load failure.
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 column 'OrderDetails' does not exist.
Why it's wrong here
If it didn't exist, the Editor would error.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume a successful preview in Power Query Editor guarantees a successful data load, ignoring that the editor may use cached data or a different authentication context than the actual refresh.
Detailed technical explanation
How to think about this question
Power Query Editor uses a data preview that may rely on cached metadata or a previously established connection, while 'Close & Apply' triggers a full data refresh that re-authenticates against the Azure SQL database. If the credentials are stored with a limited lifetime (e.g., Windows authentication with a timed token) or the database firewall blocks the Power BI service IP, the load fails despite a successful editor preview. This is a common scenario when using organizational accounts with multi-factor authentication or when the gateway is misconfigured.
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 database server is not accessible or credentials are missing. — The query runs successfully in Power Query Editor but fails during 'Close & Apply' because the editor uses a cached data preview, while the actual load requires a live connection to the Azure SQL database. The most likely cause is that the database server is inaccessible or the credentials are missing or expired at load time, which is a common connectivity issue in Power BI.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This PL-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PL-300 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.