The correct answer is to confirm that the S3 bucket exists and is in the same region as the Lambda function, because a ResourceNotFoundException typically means the Lambda function ARN specified in the S3 event notification configuration is incorrect, malformed, or points to a deleted function. S3 uses this ARN to invoke the Lambda function, and if the ARN does not match an existing, active function in the same region, the invocation fails with this error. On the AWS Certified Developer Associate DVA-C02 exam, this scenario tests your understanding of cross-service permissions and event notification setup, often appearing as a trap where candidates overlook region mismatch or ARN typos. A common memory tip is "ARN and region must align" — always verify the function ARN in the S3 bucket’s notification configuration matches the actual Lambda function, and ensure both resources reside in the same AWS region to avoid silent invocation failures.
DVA-C02 Troubleshooting and Optimization Practice Question
This DVA-C02 practice question tests your understanding of troubleshooting and optimization. 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.
A company uses AWS Lambda functions that are invoked by an Amazon S3 bucket notification. The function sometimes fails with a 'ResourceNotFoundException' for the S3 bucket. Which THREE steps should the developer take to resolve the issue?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Check the S3 bucket notification configuration for the correct Lambda function ARN.
Option B is correct because the 'ResourceNotFoundException' indicates that the Lambda function ARN specified in the S3 bucket notification configuration is incorrect or does not match the actual function ARN. S3 uses the notification configuration to invoke the Lambda function, and if the ARN is malformed, outdated, or points to a deleted function, S3 will throw this error. Verifying and correcting the ARN in the S3 event notification ensures S3 can successfully invoke the Lambda function.
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.
✗
Ensure the S3 bucket has versioning enabled.
Why it's wrong here
Versioning is not related to ResourceNotFoundException.
✓
Check the S3 bucket notification configuration for the correct Lambda function ARN.
Why this is correct
Incorrect ARN can cause the function not to be invoked.
Related concept
Read the scenario before looking for a memorised answer.
✓
Verify that the Lambda execution role has permissions to read from the S3 bucket.
Why this is correct
The role needs s3:GetObject to access the object.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase the Lambda function timeout.
Why it's wrong here
Timeout does not cause ResourceNotFoundException.
✓
Confirm that the S3 bucket exists and is in the same region as the Lambda function.
Why this is correct
Cross-region notifications are not supported for S3 to Lambda.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'ResourceNotFoundException' with a permissions issue (Option C) or a timeout issue (Option D), but the error specifically indicates the target resource (the Lambda function) is not found, not that access is denied or execution is slow.
Detailed technical explanation
How to think about this question
Under the hood, S3 bucket notifications use a resource-based policy on the Lambda function to allow S3 to invoke it, and the notification configuration stores the function ARN. If the ARN is incorrect (e.g., due to a typo, cross-account mismatch, or function deletion), S3's invocation request fails with a 'ResourceNotFoundException' before the function even executes. In real-world scenarios, this often occurs after a function is redeployed with a new ARN (e.g., after a version update) without updating the S3 notification configuration.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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.
Troubleshooting and Optimization — This question tests Troubleshooting and Optimization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Check the S3 bucket notification configuration for the correct Lambda function ARN. — Option B is correct because the 'ResourceNotFoundException' indicates that the Lambda function ARN specified in the S3 bucket notification configuration is incorrect or does not match the actual function ARN. S3 uses the notification configuration to invoke the Lambda function, and if the ARN is malformed, outdated, or points to a deleted function, S3 will throw this error. Verifying and correcting the ARN in the S3 event notification ensures S3 can successfully invoke the Lambda function.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A developer is debugging an AWS Lambda function that is invoked by an Amazon S3 bucket notification. The function fails with an 'AccessDenied' error when trying to read an object from the same bucket. What should the developer check first?
easy
A.Check if S3 bucket versioning is enabled.
B.Verify that the S3 bucket uses server-side encryption with AWS KMS.
C.Ensure the S3 bucket is not blocked by S3 Block Public Access.
✓ D.Review the Lambda function's execution role for s3:GetObject permission.
Why D: Option D is correct because the Lambda execution role must have s3:GetObject permission for the bucket. Option A is wrong because S3 Block Public Access does not affect Lambda access. Option B is wrong because encryption settings do not cause AccessDenied if permissions are correct. Option C is wrong because bucket versioning is not related to access.
Variation 2. A developer is troubleshooting an AWS Lambda function that is invoked by an Amazon S3 bucket notification. The function processes new objects and writes results to a DynamoDB table. Recently, some objects are not being processed. The developer checks the CloudWatch Logs for the Lambda function and sees no errors. Which TWO actions should the developer take to investigate the issue?
hard
A.Enable DynamoDB Streams on the table and process records.
B.Increase the Lambda function's memory allocation.
✓ C.Check the S3 bucket notification configuration to ensure it is properly set for the correct events.
✓ D.Configure a dead-letter queue on the Lambda function to capture unprocessed events.
E.Review the Lambda function's CloudWatch Logs for timeout messages.
Why C: Options B and D are correct. Option B: S3 event notifications can fail if the event is not configured correctly; checking the bucket notification configuration ensures the events are being sent. Option D: Lambda dead-letter queues (DLQ) capture events that failed to be processed; if configured, they can reveal unprocessed events. Option A is wrong because the function logs show no errors, indicating the function is not invoked for those objects. Option C is wrong because DynamoDB stream is not involved in this flow. Option E is wrong because the function is invoked, but the issue is before invocation.
Last reviewed: Jun 24, 2026
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This DVA-C02 practice question is part of Courseiva's free Amazon Web Services 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 DVA-C02 exam.
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