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HTTP Status Code
407 Proxy Authentication Required
Client ErrorThe client must authenticate with a proxy before the request can be forwarded.
HTTP status code reference, response example, common causes, fixes, and related status codes.
What does HTTP 407 Proxy Authentication Required mean?
HTTP 407 Proxy Authentication Required is a status code sent by a server to indicate the result of an HTTP request.
Status codes help browsers, APIs, apps, and backend systems understand whether a request succeeded, failed, was redirected, or needs additional action.
In practice, HTTP 407 Proxy Authentication Required usually appears when a server responds under specific request, validation, permission, or infrastructure conditions.
Response example
HTTP/1.1 407 Proxy Authentication Required Proxy-Authenticate: Basic realm="proxy"
HTTP example
HTTP/1.1 407 Proxy Authentication Required
Relevant headers
Proxy-Authenticate
Proxy-Authenticate: Basic realm="proxy"
Proxy-Authorization
Proxy-Authorization: Basic dXNlcjpwYXNz
Common causes
- Corporate or network proxy requires authentication
- Missing or invalid proxy credentials
- Misconfigured proxy settings in the client
How to fix it
- Provide valid proxy credentials
- Configure the HTTP client with the correct proxy authentication settings
- Check with your network team if the proxy requires specific credential formats
Common mistakes
- Assuming the status code alone explains the full backend issue
- Ignoring related response headers that add important context
- Treating temporary errors as permanent failures
- Retrying too aggressively without checking the cause
- Debugging the frontend only when the problem is server-side
How browsers and APIs use it
Browsers, APIs, and backend services use HTTP status codes to understand the outcome of a request. Depending on the status code, an application may render content, retry a request, redirect the user, show an error, or trigger a different flow in the client or server.
Practical developer insight
407 is the proxy equivalent of 401. It is most common in enterprise environments where outbound traffic routes through an authenticated proxy. The client should resend the request with a Proxy-Authorization header.
Client-side example
if (response.status === 407) {
console.error("Proxy authentication required — check proxy configuration.");
}