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Question 89 of 100
Error Handling & Debugging
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Q89: How Do You Troubleshoot and Handle HTTP 401 Unauthorized Errors?
🚨Core Concept
How Do You Troubleshoot and Handle HTTP 401 Unauthorized Errors?
Key Takeaways & Architecture Summary
- ✓Verify that the Authorization header is spelled correctly.
- ✓Confirm that bearer tokens are formatted correctly (e.g. Bearer token-value).
- ✓Check that access tokens are not expired.
Direct Answer Summary
An HTTP 401 Unauthorized error indicates that the request lack valid credentials or the client identity cannot be verified. Troubleshooting requires checking the spelling of the `Authorization` header, verifying that the token hasn't expired, and renewing the session using a refresh token flow.
⚠️ Senior Engineering Warning (Red Flag)
Never send raw username and password strings in plain headers without authorization wrappers. Verify that your auth methods use standard Bearer, Basic, or API Key configurations.
💡 STAR Architectural Explanation & Pro Tip
Enforcing robust token validation prevents security bypasses. Test suites should always include negative paths using expired tokens to confirm authorization barriers are active.
PlaywrightApiTest.ts
Playwright API// Verify dynamic authentication rejection in Playwright
const res = await apiContext.get('/api/v1/secure', {
headers: { 'Authorization': 'Bearer expired_token' }
});
expect(res.status()).toBe(401);