PAS-C01 Operations and Maintenance Practice Question
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?
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 instances are failing health checks.
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.
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 SSL certificate on the ALB has expired.
Why it's wrong here
Expired SSL certificate would cause SSL handshake failures, not 503 errors.
- ✗
Security groups allow too much traffic.
Why it's wrong here
Security groups would cause connection timeouts, not 503 errors.
- ✓
The target instances are failing health checks.
Why this is correct
Unhealthy targets cause ALB to return 503 errors.
- ✗
The ALB is out of capacity.
Why it's wrong here
ALB automatically scales to handle traffic; out of capacity is rare.
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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.