Experiencing the “failed to load resource: net::err_file_not_found” error when browsing the web can be frustrating. This error typically appears when a website attempts to load a resource like an image, CSS file, or JavaScript file, but the file cannot be found on the server.
There are a few potential causes and solutions for this error that are worth trying to resolve the issue.
Checking for Typos or Broken Links
A common source of the “failed to load resource” error is simply a typo or broken link on the website code. Web developers may have made a slight mistake when specifying the file path or URL for a resource.
To troubleshoot for typos:
- Try refreshing the page or reloading the website. This may force resources to reload.
- Check the browser console for the exact file path that failed to load. Compare it to other resources that loaded properly.
- If a file in the same folder loaded fine, check for minor typos or differences in the problem file path.
- Ask the site owner to audit their code for broken links or incorrect paths.
Refreshing the page or fixing any minor text errors can often resolve this easily.
Investigating Server, Cache, and CDN Issues
In other cases, the resource may fail to load due to problems with the web server setup, cached files, or Content Delivery Network (CDN) configuration. Some things to investigate:
- Check if the server has errors or is experiencing downtime when you try to load the problem file.
- Try clearing your browser cache and cookies. An outdated cached copy of the file may be causing issues.
- The site may rely on a CDN to distribute resources. There could be misconfigured CDN settings for expirations or origin domains.
- Ask the site owner to verify the server, cache, and CDN setup. Misconfigurations here can prevent files from being accessible.
Addressing factors on the hosting infrastructure could help resolve missing resource problems.
Incorrect Permissions Set on Files or Folders
The application files and folders on the server have assigned permissions and ownership settings. If these settings are too restrictive, the web application may be blocked from loading necessary resources.
Some guidelines for checking permissions:
- The web application files/folders must be readable by the system user or group running the web server process.
- Parent folders in the file path should provide executable access to allow accessing subfolders and files.
- Ask the hosting provider to verify file and folder permissions are not too locked down. Loosening restrictions may allow loading resources correctly.
Adjusting permissions is a common requirement to fix failed resource-loading scenarios caused by access blocks.
Identifying Blocked Resources from Firewalls or Security Rules
On corporate networks or restricted public Wi-Fi, there are often security controls enabled such as firewall rules, proxies, DNS filtering, or application layer filters. These solutions are intended to protect users and prevent access to malicious sites.
However, they can also end up blocking legitimate resources from being loaded by mistake.
Some signs this may be happening:
- The failed resource has an unusual file extension not common for websites (.exe, .tgz, etc.)
- Access works fine on cellular networks but not on office/WiFi networks
- The organization has discussed security mechanisms that can filter web content
Getting exceptions added to allowlist legitimate resources is the best way to address blocked files from security policies stripping them out.
Fixing Problems with Custom Website Extensions
For more complex websites built with extensive custom programming, resource loading failures may actually indicate bugs or errors with the site code itself.
If you have eliminated the other factors as causes:
- Review any recent website extensions, plugins or components added to the platform.
- Check if the failure started after an update to custom site software.
- Alert the development team to troubleshoot faults with custom extensions causing cascading resource issues.
Fixing flaws in custom website logic can resolve some stubborn failed resource errors not explained by the above factors.
Conclusion
Tracking down the “failed to load resource: net::err_file_not_found” message may require some trial and error with potential causes. Check for simple issues like typos first before diving deeper into complex software bugs.
Pay attention to any changes preceding the error, like updates or new security policies that could block resources. Ideally, site owners should proactively test and monitor for failed assets before impacting site visitors significantly.
Addressing root causes requires understanding the web ecosystem delivering resources from servers to browsers. Collaborating with network administrators and developers may help unlock fixes faster.
