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220-1102 Practice Question: A user's browser is displaying a warning that the…
A user's browser is displaying a warning that the website's certificate is not trusted, even though the URL is correct. The technician checks the date and time on the computer and finds it is set to 2019. What is the most likely cause of the certificate warning?
⚠ Common exam trap
CompTIA A+ often tests the candidate's ability to distinguish between certificate revocation, corruption, and simple date/time misconfiguration, trapping those who overthink the problem or assume a security breach (like a proxy) when the most basic setting is wrong.
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 system date is incorrect, causing certificate validation to fail.
The system date is set to 2019, which is outside the certificate's validity period. SSL/TLS certificates have a specific notBefore and notAfter date range; when the client's clock is outside this range, the browser rejects the certificate as untrusted. This is the most direct and common cause of the warning given the symptom and the technician's finding.
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The website's SSL certificate has been revoked.
Why it's wrong here
A revoked SSL certificate indicates that the certificate authority (CA) has explicitly invalidated it before its natural expiration date, usually due to compromise, misissuance, or key loss. Browsers check revocation status via Certificate Revocation Lists (CRLs) or Online Certificate Status Protocol (OCSP). A warning for a revoked certificate would specifically state revocation, which is distinct from a failure to validate due to an incorrect system date, as the certificate's validity period itself might still be current.
- ✗
The browser's certificate store is corrupted.
Why it's wrong here
A corrupted certificate store would cause failures across all HTTPS sites, not a single certificate warning tied to an incorrect system clock. The browser validates certificate trust by checking the certificate’s validity period against the current date; a 2019 date places the certificate outside its valid range, triggering the warning. This option is tempting because a corrupted store does produce trust errors, but those errors are widespread and unrelated to date/time mismatches, which are resolved by synchronising the clock.
- ✓
The system date is incorrect, causing certificate validation to fail.
Why this is correct
SSL/TLS certificates contain specific 'valid from' and 'valid to' date ranges, which are cryptographically signed by the Certificate Authority. If the client system's date and time fall outside this defined validity period, the browser's cryptographic validation process will fail, as it cannot confirm the certificate is currently legitimate. An incorrect system date, such as being set to 2019 when the certificate is valid for a later period, directly causes this validation failure and triggers a security warning.
- ✗
The user is connected to a malicious proxy.
Why it's wrong here
A malicious proxy server could intercept encrypted traffic, decrypt it, and then re-encrypt it using its own self-signed or untrusted certificate before forwarding it to the user. This 'man-in-the-middle' attack would typically cause the browser to display a warning about an untrusted certificate authority or an invalid certificate chain, as the proxy's certificate would not be recognized by the browser's trust store. While this causes certificate errors, it's distinct from a date-specific validation failure, which points more directly to the client's system clock being out of sync.
Go deeper
Related to this question
Learn chapter
Virtualization and Client-Side
Key term
Certificate warning
A certificate warning is a security alert a web browser or application displays when it cannot fully trust the digital certificate presented by a website or service.
Key term
Transport Layer Security
Transport Layer Security (TLS) is a cryptographic protocol that provides secure, encrypted communication between two devices over a network, such as between a web browser and a server.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1202 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 220-1202 exam.