PAS-C01 Operations and Maintenance Practice Question
A company runs its SAP landscape on AWS and uses an Application Load Balancer (ALB) to distribute traffic to multiple web dispatchers. The operations team notices that some requests are failing with 503 errors. What is the most likely cause?
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
✓
The target group health checks are failing, causing the ALB to mark instances as unhealthy.
503 errors from an ALB typically indicate that the target instances are unhealthy or the ALB cannot route traffic to them, often due to failed health checks. Option A is wrong because security groups blocking traffic would cause 504 or timeout errors, not 503. Option B is wrong because an expired SSL certificate on the ALB would cause 502 errors (bad gateway), not 503. Option C is wrong because CloudFront is not in the path; the question describes an ALB distributing traffic directly to web dispatchers, so CloudFront misconfiguration is irrelevant.
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 security groups for the ALB are blocking incoming traffic.
Why it's wrong here
Blocked traffic would result in connection timeouts, not 503.
- ✗
The SSL certificate on the ALB has expired.
Why it's wrong here
SSL errors typically result in 502 Bad Gateway.
- ✗
The CloudFront distribution in front of the ALB is misconfigured.
Why it's wrong here
No CloudFront mentioned in the scenario.
- ✓
The target group health checks are failing, causing the ALB to mark instances as unhealthy.
Why this is correct
503 errors occur when no healthy targets are available.
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Variation 1. A company runs SAP on AWS and uses an Application Load Balancer (ALB) to distribute traffic to web dispatchers. The operations team notices that some requests are failing with 503 errors. What is the MOST likely cause?
medium- A.The SSL certificate on the ALB has expired.
- B.Security groups allow too much traffic.
- ✓ C.The target instances are failing health checks.
- D.The ALB is out of capacity.
Why C: 503 errors from an ALB indicate that the target instances are unhealthy or not responding. Option A is wrong because 503 errors are not caused by SSL certificate issues. Option B is wrong because security groups would cause connection timeouts, not 503. Option D is wrong because ALB capacity is automatically scaled.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PAS-C01 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 PAS-C01 exam.