Quick Answer
The answer is that the web server service is not running on the cloud VM. This is the most likely cause because when troubleshooting web server service not running on cloud VM, you must isolate the issue layer by layer: the security group allows HTTP from any source, the OS firewall is disabled, and ping succeeds, confirming network and transport layer connectivity. The only remaining barrier is the application layer—if the web server software (like Apache, Nginx, or IIS) is stopped, it won’t listen on TCP port 80, so HTTP requests are refused despite open network paths. On the CompTIA Cloud+ CV0-004 exam, this scenario tests your ability to differentiate between cloud security group rules, OS-level firewalls, and application service states—a common trap is assuming a misconfigured security group when the real issue is a stopped service. Remember the mnemonic “Ping works, port fails, check the service rails” to quickly recall that successful ICMP but failed HTTP points to the application layer.
This CV0-004 practice question tests your understanding of troubleshooting. 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 cloud engineer is troubleshooting an issue where users cannot connect to a web application hosted on a cloud VM. The VM's security group allows HTTP (port 80) from 0.0.0.0/0, and the VM's OS firewall is disabled. The engineer can ping the VM's public IP from the internet. What is the most likely cause of the issue?
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.
OS firewall is blocking port 80
Why wrong: The OS firewall is disabled.
Incorrect routing table on the VM
Why wrong: Ping works, so routing is functional.
Security group rule is applied to the wrong subnet
Why wrong: The security group allows HTTP from anywhere, so it should work.
Web server service is not running on the VM
If the web server is not running, it won't respond on port 80, even though the network allows it.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Web server service is not running on the VM
Since the OS firewall is disabled and the security group allows HTTP from 0.0.0.0/0, the only remaining layer that could block connectivity is the application itself. If the web server service (e.g., Apache, Nginx, IIS) is not running on the VM, it will not listen on TCP port 80, so HTTP requests will be refused even though network-level access is permitted. The ability to ping the VM confirms IP-level reachability, isolating the issue to the application layer.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
OS firewall is blocking port 80
Why it's wrong here
The OS firewall is disabled.
Incorrect routing table on the VM
Why it's wrong here
Ping works, so routing is functional.
Security group rule is applied to the wrong subnet
Why it's wrong here
The security group allows HTTP from anywhere, so it should work.
Web server service is not running on the VM
Why this is correct
If the web server is not running, it won't respond on port 80, even though the network allows it.
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.
Common exam traps
The trap here is that candidates assume a ping success implies all services are reachable, but ICMP (ping) operates at the network layer (Layer 3) and does not test TCP port availability, so a running web server is required for HTTP connectivity.
Detailed technical explanation
When a web server service is not running, the VM's TCP stack will respond with a RST (reset) packet to any incoming SYN on port 80, causing the client to receive a 'Connection refused' error. This differs from a firewall block, which typically drops the packet silently or sends an ICMP unreachable. In cloud environments, security groups act as a virtual firewall at the hypervisor level, while the OS firewall (e.g., iptables, Windows Firewall) operates within the VM; disabling the OS firewall removes that layer, making the web server service the critical component.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Troubleshooting — study guide chapter
Learn the concepts, then practise the questions
Troubleshooting practice questions
Targeted practice on this topic area only
All CV0-004 questions
499 questions across all exam domains
CompTIA Cloud+ CV0-004 study guide
Full concept coverage aligned to exam objectives
CV0-004 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise CV0-004 questions linked to Operations and Support.
Practise CV0-004 questions linked to Cloud Architecture and Design.
Practise CV0-004 questions linked to Security.
Practise CV0-004 questions linked to Deployment.
Practise CV0-004 questions linked to Troubleshooting.
Practise CV0-004 questions linked to CV0-004 fundamentals.
Practise CV0-004 questions linked to CV0-004 scenario.
Practise CV0-004 questions linked to CV0-004 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Troubleshooting — This question tests Troubleshooting — Read the scenario before looking for a memorised answer..
The correct answer is: Web server service is not running on the VM — Since the OS firewall is disabled and the security group allows HTTP from 0.0.0.0/0, the only remaining layer that could block connectivity is the application itself. If the web server service (e.g., Apache, Nginx, IIS) is not running on the VM, it will not listen on TCP port 80, so HTTP requests will be refused even though network-level access is permitted. The ability to ping the VM confirms IP-level reachability, isolating the issue to the application layer.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
Keep practising
Last reviewed: Jun 11, 2026
This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 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.