200-901 Understanding and Using APIs Practice Question

A Webex API request returns a 401 Unauthorized error. The developer has already obtained an access token. 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

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Invalid access token or expired token

A 401 error typically indicates an invalid or expired token, or missing Authorization header.

Answer analysis

For each option: why learners choose it and why it is or isn't the right answer here.

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Invalid access token or expired token
Why this is correct
A 401 response means the request lacked valid authentication credentials, so with a token already supplied the token itself is rejected — expired, malformed, or issued for the wrong integration. Authorisation failures on a valid token would instead return 403 Forbidden.
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Resource not found
Why it's wrong here
A missing resource yields 404 Not Found, not 401, so this cannot explain the response. It is tempting because a malformed or mistyped endpoint path is a common API mistake, making resource-not-found the right diagnosis when the status code returned is 404.
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Rate limit exceeded
Why it's wrong here
A 401 signals the token was rejected as invalid or expired, so the credential itself is the problem; rate limiting returns 429, not 401. Throttling limits are tempting because heavy API use does trigger failures, but they manifest as 429 responses with retry headers, making this the wrong cause here.
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Server internal error
Why it's wrong here
A server-side fault produces 5xx responses such as 500 Internal Server Error, not 401, which indicates the request lacked valid authentication. It is tempting because backend failures are frequent causes of API errors, making server internal error correct when the returned status falls in the 500 range.

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