PCNSE Secure Access and VPN Practice Question
An administrator is configuring GlobalProtect with certificate authentication. The portal is configured to use a certificate profile that validates client certificates against a trusted CA. Users report that authentication fails with the error 'Certificate validation failed'. The administrator has verified that the client certificates are issued by the correct CA and are not expired. What is the most likely cause of the failure?
⚠ Common exam trap
The trap here is focusing on CA trust and expiration while overlooking the extended key usage requirement in the certificate profile.
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 certificate profile is not configured to allow the certificate's extended key usage (EKU) for client authentication.
Certificate validation in GlobalProtect checks multiple attributes, including EKU. If the certificate profile does not allow the EKU present in the client certificate, validation fails even if the certificate is from a trusted CA and not expired. The error message 'Certificate validation failed' is a strong indicator of such a mismatch.
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 certificate revocation list (CRL) is not configured in the certificate profile.
Why it's wrong here
While a missing CRL could cause validation failure if revocation checking is required, the scenario states that the certificates are valid and not expired. If CRL checking were the issue, the error might mention revocation. However, without explicit configuration requiring CRL, it is less likely to be the cause. The more common cause is EKU mismatch.
- ✓
The certificate profile is not configured to allow the certificate's extended key usage (EKU) for client authentication.
Why this is correct
In a certificate profile, you must specify the EKU that the client certificate must contain, such as 'clientAuth'. If the profile does not permit the EKU present in the certificate, validation fails. The error 'Certificate validation failed' often indicates this mismatch, even if the certificate is otherwise valid and from a trusted CA.
- ✗
The client certificate is not installed in the user's personal certificate store.
Why it's wrong here
If the client certificate were not installed, the user would not be able to select it during authentication, and the error would likely indicate that no certificate was presented. The error 'Certificate validation failed' implies that a certificate was presented but failed validation, so the certificate is present but not meeting validation criteria.
- ✗
The GlobalProtect portal is not configured with the correct SSL/TLS service profile.
Why it's wrong here
The SSL/TLS service profile is used for the portal's server certificate and TLS settings, not for validating client certificates. While an incorrect SSL/TLS service profile could cause connection issues, it would typically result in a different error, such as a TLS handshake failure, not a certificate validation failure specific to client authentication.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Palo Alto Networks exam blueprint
This PCNSE practice question is part of Courseiva's free Palo Alto Networks 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 PCNSE exam.