401 Unauthorized Error in API: Causes and Fixes

Discover how to fix a 401 unauthorized error in the API. Our API Integration Support team is ready to assist with any queries or concerns.

401 Unauthorized Error in API: Causes and Fixes

If you’ve ever tried to access a website or API and received a “401 Unauthorized” error, you’re not alone. This is one of the most common HTTP status codes users encounter, especially when dealing with secured content or services.

Today, our Experts will take us through the 401 Unauthorized Error, why it happens, and provide a step-by-step checklist to resolve it.

What is the 401 Unauthorized Error?

The 401 Unauthorized Error is an HTTP response status code that means the server cannot process the request because it lacks valid authentication credentials.

This error usually occurs when no authentication is provided, incorrect or expired credentials are used or the user has insufficient permissions.

Common Causes of the 401 Unauthorized Error

• If we don’t include proper credentials like the API key, token, or username/password, the server will deny access.
• In systems using OAuth or JWT (JSON Web Tokens), tokens eventually expire. If we are using an expired token, we will get a 401 error until it’s refreshed.
• Sometimes we are authenticated but still lack the required permissions to access a specific resource.
• The server might block requests from certain users or IP addresses, resulting in a 401 error.
• Browsers or proxy servers can cache unauthorized responses, causing the error to persist even after the credentials have been corrected.
• Incorrect server settings can lead to valid credentials being rejected by mistake.

How to Fix the 401 Unauthorized Error

• First, double-check that we are using the correct API key or authentication token. Typos and expired keys are common culprits.
  If unsure about the credentials, check the account dashboard or contact the API provider.
• Also, make sure the authentication token is correctly placed in the request headers. For example, with curl, we can use:

  curl -H "Authorization: Bearer YOUR_API_KEY" https://api.example.com/resourceCopy Code
• Furthermore, if we are using token-based authentication, make sure the token hasn’t expired. If it has, refresh it according to the API documentation.

  Moreover, each API has specific authentication requirements. So, check the documentation carefully to make sure we are following the correct procedure.

  For example, if we are using Google Maps API or other services, refer to their authentication guidelines to avoid mistakes.
• Sometimes, a simple typo in the URL causes the server to reject the request. Make sure the web address we are trying to access is correct.
• Also, outdated or corrupt DNS records can interfere with server connections. Flushing the DNS might resolve the issue.
  We can flush the DNS with these commands:
  1. Windows:

     ipconfig /flushdnsCopy Code
  2. macOS:

     sudo killall -HUP mDNSResponderCopy Code
  3. Linux:

     sudo systemd-resolve –flush-cachesCopy Code

     Or

     sudo /etc/init.d/nscd restartCopy Code
• Also, old cookies or cached sessions can cause repeated authentication errors. To fix this, go to the Browser Settings> Privacy or History and select Clear Cookies and Cache. Then, restart the browser.
• If we were logged in when the error occurred, logging out and then logging back in can refresh the session and resolve the problem.

If none of the above steps work, it may be a server-side issue. Contact the website administrator or support team. Most sites have a “Contact Us” page where you can report the problem.

[Need assistance with a different issue? Our team is available 24/7.]

Conclusion

The 401 Unauthorized Error is easily fixable with the right steps.

In short, our Support Engineers demonstrated how to fix a 401 unauthorized error in the API.