Network Error

This error is how the popular Axios HTTP client library reports network failures when making requests. The generic error message Network Error appears when Axios cannot establish a connection to the requested URL or receives no response from the server.

Unlike “Failed to fetch” from the native Fetch API, “Network Error” is specific to Axios and indicates a fundamental connectivity problem rather than an HTTP status error. This error should be investigated as it represents a real request failure affecting your application.

Network Error is one of the most common JavaScript errors, but it provides very little information. Consider adding TrackJS’s Axios integration to capture these missing details automatically, showing you exactly which requests are failing.

Other browsers and libraries show similar errors:

• Chrome Fetch API: Failed to fetch
• Safari Fetch API: Load failed
• Firefox Fetch API: NetworkError when attempting to fetch resource

The Problem

This error is thrown by the Axios library when the underlying network request fails completely. The error will NOT occur if the server returns data, even with failed response codes like 404 or 500 status codes.

Your application is making an Axios request that cannot connect to the server. This is typically caused by environmental factors like network connectivity issues, ad blockers, or server configuration changes rather than problems with your code.

Important: This error means the request never reached the server or the server never responded. It’s different from HTTP errors like 404 or 500, which indicate the server responded but with an error status code.

Understanding the Root Cause

The “Network Error” from Axios can have several different causes, and identifying the correct one is crucial for applying the right fix. Here are the most common culprits:

1. CORS (Cross-Origin Resource Sharing) Issues

Most common cause: CORS is a browser security feature that blocks requests between different domains unless the server explicitly allows it. When your web application tries to make an Axios request to a different domain without proper CORS headers, the browser blocks the request.

How to identify: Check the browser console for additional CORS-related error messages alongside “Network Error.”

2. Network Connectivity Problems

The most straightforward cause - the device has lost internet connectivity, has poor network conditions, or network infrastructure is blocking the request.

Common scenarios:

• Server is offline or unreachable
• DNS resolution failures preventing domain lookup
• Firewall or corporate network blocking the request
• Mobile device losing cellular or WiFi connectivity

3. Ad Blockers and Browser Extensions

Ad blockers and privacy extensions frequently block requests to certain domains or URLs that match their filter lists, causing Axios requests to fail.

How to identify: Test your application with ad blockers disabled. If the error disappears, ad blockers are interfering with your requests.

4. Incorrect URL Configuration

Simple but common errors in request configuration can cause network failures.

Common mistakes:

• Wrong protocol (http vs https)
• Incorrect port numbers
• Typos in domain names or endpoints
• Missing or malformed base URLs

5. SSL/TLS Certificate Issues

Browsers will refuse connections to servers with invalid, expired, or self-signed SSL certificates.

How to identify: Try accessing the API URL directly in the browser to check for certificate warnings.

6. Development Environment Issues

Common development problems:

• API server not running locally
• Wrong localhost port configuration
• Missing environment variables for API endpoints
• Development proxy configuration issues

How to Fix “Network Error”

Quick Troubleshooting Checklist

• Verify internet connectivity
• Check the API URL for typos and correct configuration
• Test the API endpoint directly in a browser
• Look for CORS error messages in browser console
• Temporarily disable ad blockers and browser extensions
• Confirm the target server is running and accessible

If the quick fixes don’t work, follow these detailed steps to debug and resolve the issue:

Step 1: Check Browser DevTools and Telemetry

Open DevTools (F12 or right-click → Inspect), go to the Network tab, reproduce the error, and look for your failed request - it will show as red or canceled.

With TrackJS, examine the Telemetry Timeline for the specific request details:

The telemetry timeline shows the exact URL being requested, timing information, and other context that helps identify why the Axios request failed.

Important: By default, Axios only shows generic “Network Error” messages, hiding valuable debugging information. TrackJS provides a dedicated Axios integration that extracts the HTTP method and URL from failed requests, giving you detailed error messages like “Network Error GET: https://api.example.com/users” instead of just “Network Error”.

Step 2: Implement Comprehensive Error Handling

Add detailed error handling to distinguish between different types of Axios failures. Check for specific error codes like ERR_NETWORK in modern Axios versions, or the legacy “Network Error” message. Handle cases where the server responds with an error status versus cases where no response is received at all.

// Add response interceptor to capture network errors
axios.interceptors.response.use(
    // Pass through successful responses unchanged
    (response) => response,

    // Handle errors and send details to TrackJS
    (error) => {
        // Capture a formatted error with method and URL
        if (error.config && error.config.method && error.config.url) {
            TrackJS.track(`Network Error ${error.config.method.toUpperCase()}: ${error.config.url}`);
        } else {
            // Fallback for errors without config
            TrackJS.track(error);
        }

        // Re-throw the error so other error handlers can process it
        return Promise.reject(error);
    }
);

Step 3: Fix CORS Issues

For development, configure your development server to proxy API requests to avoid CORS issues. For production, ensure your API server returns proper CORS headers allowing your domain to make requests.

Step 4: Implement Retry Logic

For transient network issues, implement intelligent retry mechanisms with exponential backoff. Don’t retry client errors (4xx status codes), but do retry network connectivity failures and server errors.

Step 5: Handle Ad Blocker Interference

Implement graceful handling for ad blocker interference by detecting “Network Error” patterns and providing fallback functionality or user notifications about limited features.

Step 6: Monitor Network Errors in Production

Set up comprehensive monitoring to track and analyze network errors across your user base. Error monitoring services like TrackJS automatically capture Axios network errors with context about the request URL, user environment, and network conditions.

This visibility helps you identify patterns like geographic regions with connectivity issues, specific API endpoints failing frequently, correlation between network errors and user behavior, and the impact of ad blockers on your application functionality.

When to Ignore This Error

“Network Error” from Axios should rarely be ignored, as it indicates real connectivity problems affecting your users. However, consider the context:

• Temporary network interruptions: Brief connectivity losses on mobile devices
• User-initiated navigation: Users leaving the page before requests complete
• Ad blocker interference: If you have proper fallback handling in place

However, investigate further when you see:

• Consistent failures from specific regions: May indicate server accessibility issues
• High error rates during peak times: Could suggest server capacity problems
• Sudden increases after deployments: May indicate configuration changes affecting connectivity
• Errors affecting core functionality: Any network failures that prevent users from accomplishing critical tasks

Summary

Axios “Network Error” typically indicates genuine connectivity issues, CORS problems, or server unavailability that require investigation. Unlike HTTP status errors, this means no server response was received at all. The key to resolution is systematic diagnosis using browser DevTools and telemetry data, followed by appropriate fixes like CORS configuration, robust error handling, and retry mechanisms.

Focus your debugging efforts on connectivity, CORS settings, and server availability rather than response content or status codes. This error represents a real barrier to your users accessing your application’s functionality.