Toronto SEO
All HTTP status codes
4xx Client Error
RFC 9110

407 Proxy Authentication Required

The client must authenticate with a proxy before the request can proceed.

What it means

HTTP 407 Proxy Authentication Required is similar to 401 but indicates that authentication must occur with the proxy server, not the origin. The response includes a Proxy-Authenticate header.

When it's used

Corporate networks with authenticated proxies, paid VPN endpoints, or carrier-grade NAT requiring auth.

Common causes
  • Corporate proxy requires login
  • VPN authentication expired
  • Misconfigured proxy credentials in client
How to fix it
  • Provide credentials via Proxy-Authorization header
  • Configure your HTTP client with the proxy username/password
  • Contact your network administrator for the correct proxy credentials
Example response
HTTP/1.1 407 Proxy Authentication Required
Proxy-Authenticate: Basic realm="corporate-proxy"
SEO impact

Not relevant to public-web SEO.