The answer is that the Cobra SDK AuthenticationError is most likely caused by an incorrect username or password. This error occurs because the SDK’s login method sends an HTTP POST to the APIC’s `/api/aaaLogin.json` endpoint, and when the credentials do not match a valid local or AAA-authenticated user, the APIC returns a non-200 response that triggers the `AuthenticationError` exception. On the Cisco DCCOR 350-601 exam, this scenario tests your understanding of ACI authentication flows and the specific error handling within the Cobra SDK—a common trap is assuming the error stems from network connectivity or certificate issues rather than credential mismatch. A reliable memory tip is to associate “AuthError” with “AuthCredentials”: if the script fails at login, always verify the username and password first, as the SDK will not raise this exception for any other reason.
350-601 Automation Practice Question
This 350-601 practice question tests your understanding of automation. 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.
Exhibit
from cobra.mit.access import MoDirectory
from cobra.mit.session import LoginSession
session = LoginSession('https://apic-ip', 'admin', 'password')
md = MoDirectory(session)
md.login()
print(md.lookupByClass('fvTenant'))
Refer to the exhibit. A Python script using the Cisco ACI Cobra SDK fails with 'AuthenticationError'. Which of the following is the most likely cause?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The username or password is incorrect
The 'AuthenticationError' in the Cisco ACI Cobra SDK indicates that the APIC rejected the login credentials. This error is raised specifically when the username or password provided in the script's login method (e.g., 'Login('apic_url', 'username', 'password')') does not match a valid APIC local or AAA-authenticated user. The SDK performs an HTTP POST to the APIC's '/api/aaaLogin.json' endpoint, and a non-200 response with an authentication failure triggers this exception.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 APIC URL is incorrect
Why it's wrong here
An incorrect URL would cause a connection error, not AuthenticationError.
✗
The user does not have API access
Why it's wrong here
Lack of API access typically gives an authorization error after successful authentication.
✓
The username or password is incorrect
Why this is correct
AuthenticationError directly indicates failed login due to credentials.
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.
✗
The script is missing required imports
Why it's wrong here
Missing imports cause ImportError, not AuthenticationError.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between authentication failures (wrong credentials) and authorization failures (no API access), so candidates mistakenly choose 'user does not have API access' when the error message clearly points to the login phase.
Detailed technical explanation
How to think about this question
Under the hood, the Cobra SDK uses the 'cobra.mit.access.MoDirectory' class to establish a session. The login method sends a REST payload with the username and password to the APIC's '/api/aaaLogin.json' endpoint. The APIC validates credentials against its local database or an external AAA server (e.g., RADIUS, TACACS+). If authentication fails, the APIC returns an HTTP 401 or 403 status with an error code, which the SDK interprets as an 'AuthenticationError'. In real-world scenarios, this often occurs when a password has expired or when using a domain-qualified username (e.g., 'apic#username') incorrectly.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Automation — This question tests Automation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The username or password is incorrect — The 'AuthenticationError' in the Cisco ACI Cobra SDK indicates that the APIC rejected the login credentials. This error is raised specifically when the username or password provided in the script's login method (e.g., 'Login('apic_url', 'username', 'password')') does not match a valid APIC local or AAA-authenticated user. The SDK performs an HTTP POST to the APIC's '/api/aaaLogin.json' endpoint, and a non-200 response with an authentication failure triggers this exception.
What should I do if I get this 350-601 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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