ERR_BLOCKED_BY_RESPONSE Error - 6 Ways to Fix It
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One issue that web developers and users can face while browsing is the ERR_BLOCKED_BY_RESPONSE error. This error typically occurs when a web request is blocked due to server or browser settings.
Whether you’re troubleshooting your own website or trying to fix it on the user side, understanding the cause is key to resolving it. In this guide, we’ll walk you through six practical solutions to fix this error.
The error message appears in the browser’s DevTools console, or as a full page error, and may be accompanied by details like:
- net::ERR_BLOCKED_BY_RESPONSE
- Specific headers or response issues that caused the failed to load resource
What causes ERR_BLOCKED_BY_RESPONSE?
The “ERR_BLOCKED_BY_RESPONSE” error occurs when a web request is blocked due to server, network, or client-side issues. Here are some common causes:
1. Cross-Origin Resource Sharing (CORS) Issues
Access control allow methods restrict how resources on one domain are accessed by another domain. Misconfigured CORS headers on the server that is supposed to send the resource can lead to blocked requests.
This might be confusing, so let’s illustrate it with an example:
You embed a weather widget on your site that fetches data from api.weather.com. If api.weather.com doesn’t send the Access-Control-Allow-Origin: https://yourdomain.com header, the browser blocks the response.
In such cases, the API provider needs to reconfigure their server so it sends the appropriate CORS headers.
Another example would be if your main site (www.example.com) fetches resources from a subdomain (api.example.com). Without correct CORS headers, requests between these subdomains can fail.
2. Misconfigured Server Headers
Incorrect server headers, such as Content-Security-Policy or X-Frame-Options, can block certain requests and trigger the error.
- CSP headers restrict where scripts, styles, or other resources can load from. If the response violates the defined CSP, the browser blocks it.
- Headers like X-Frame-Options, Strict-Transport-Security, or Content-Type might be missing or misconfigured, leading to blocked responses.
For example, if you’re using Google Fonts, a CSP header can block it and trigger the ERR_BLOCKED_BY_RESPONSE in your browser.
3. Browser Extensions or Add-Ons
Certain browser extensions, especially ad blockers or security add-ons, may interfere with requests and block responses from loading.
If you’re using a third-party script, like Google Analytics or a tracking pixel from a marketing service, extensions like uBlock Origin, AdBlock, or Ghostery can block requests to known tracking or ad-serving domains.
You can try disabling such extensions or test in incognito mode to determine if one is causing the issue.
4. Network Restrictions
Firewalls, resource blocking network settings or a VPN or proxy server can restrict web requests, causing the error to appear in your console.
This can be a local device misconfiguration, a corporate firewall or country-specific network restrictions that block requests to external domains.
Visitors from specific countries or business networks with strict internet controls wouldn’t be able to access resources, thus resulting in a blocked response error.
Using a VPN or proxy server to bypass blocking policies might allow resources from different origins to load successfully.
5. Incorrect API or JavaScript Code
Errors in API endpoints or JavaScript code may send invalid requests, resulting in blocked responses.
For example, a typo or syntax error in your JavaScript sends malformed API requests – the server responds with an error, causing the browser to block the resource.
How to fix ERR_BLOCKED_BY_RESPONSE
1. Clear Browser Cache and Cookies
Cached data and cookies can sometimes cause conflicts, leading to blocked responses. To resolve this, check our dedicated article to clear browsing data in all popular browsers. After clearing your browser cache, reload the page to see if the error persists.
This step helps remove conflicting site data that could interfere with loading resources.
2. Disable Browser Extensions
Browser extensions, especially those designed for security, privacy, or content blocking, can interfere with web requests. To address this:
1. Open your browser’s Extensions or Add-ons menu.
2. Disable extensions one by one, starting with ad blockers or security tools.
3. Refresh the browser window after each change to identify the problematic extension.
Once identified, remove or update the extension to prevent further issues.
3. Verify CORS Settings on the Server
CORS issues are common causes of the ERR_BLOCKED_BY_RESPONSE error. If the server doesn’t allow resources to be accessed across different origins, it can block the request.
To resolve this, check the Access-Control-Allow-Origin header in the server’s response. Right-click on the page > Inspect, and go to the Network tab in the Developer Tools:
Reload the page and check the response headers for any issues with the allowed requests from the required domains.
If you’re fetching resources from a domain that you are managing, go to your hosting dashboard and set the appropriate CORS headers.
If the issue is with a 3rd party website – contact the owner so they can make the necessary changes on their server to fix the ERR_BLOCKED_BY_RESPONSE error.
4. Check Firewall Rules
Sometimes, firewalls or proxy server settings can block certain web requests, causing the ERR_BLOCKED_BY_RESPONSE error. To address this:
- Temporarily disable the firewall to see if the error resolves.
- If disabling resolves the issue, adjust or reset the firewall settings to allow the necessary traffic.
Updating or adjusting your firewall and proxy rules can prevent legitimate requests from being blocked.
5. Update or Reinstall Your Browser
Outdated or corrupted browser versions can lead to unexpected errors, including the ERR_BLOCKED_BY_RESPONSE error. To resolve this:
- Check for updates in your browser’s settings.
- If updates are available, install them and restart your browser.
- If the error persists, try reinstalling with the latest version from the official site.
- After reinstalling, check if the error is resolved by visiting the affected webpage.
Updating or reinstalling your browser ensures compatibility and fixes potential bugs that may cause errors.
6. Debug Using Developer Tools
If the previous fixes haven’t resolved the error, the issue may be deeper on the server-side. Use browser developer tools to identify any server-side problems:
- Open the browser’s Developer Tools (usually by pressing F12 or right-clicking and selecting Inspect).
- Go to the Network tab and refresh the page.
- Look for any failed requests marked in red.
- Check the response headers, status codes, and any error messages to identify potential issues.
- Use the information to debug server-side configurations or contact your web hosting provider for assistance.
Developer tools can provide detailed insights into server issues. If the error is due to a misconfiguration on a 3rd party server, report it so it can be addressed by the administrator responsible for that platform.
Final Thoughts on Fixing ERR_BLOCKED_BY_RESPONSE
The ERR_BLOCKED_BY_RESPONSE error can be frustrating, but it’s usually fixable with a few simple troubleshooting steps.
By clearing your browser cache, adjusting server configurations, or checking for conflicting extensions, you can often resolve the issue quickly. If the error persists, use developer tools to identify server-side issues or consult your hosting provider for further support.
If you are trying to load external resources, the issue may be outside of your control. In such cases, report it to the respective party so they can troubleshoot further.
