407
SIP
407 Proxy Authentication Required
The client must first authenticate with the proxy. The proxy returns a Proxy-Authenticate header with a challenge.
On this page
When You See This Code
When a SIP proxy requires authentication before forwarding the request. Similar to 401 but for proxy servers.
How to Fix
Resend the request with a Proxy-Authorization header containing valid credentials for the proxy.
Specification
Comparisons
Compare With
Guides
401 Unauthorized vs 403 Forbidden: When to Use Each
Security & Authentication
SIP Response Codes: Understanding VoIP Call Flow
Real-Time Protocols
SIP Call Flow: Understanding Session Setup
Real-Time Protocols
WebRTC Signaling with SIP and WebSocket
Real-Time Protocols
RFC 3261: SIP Protocol Deep Dive
Protocol Deep Dives
TLS 1.3: Faster, Simpler, More Secure
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Frequently Asked Questions
What is SIP 407 Proxy Authentication Required?
The client must first authenticate with the proxy. The proxy returns a Proxy-Authenticate header with a challenge.
When do you see SIP 407 Proxy Authentication Required?
When a SIP proxy requires authentication before forwarding the request. Similar to 401 but for proxy servers.
How to fix SIP 407 Proxy Authentication Required?
Resend the request with a Proxy-Authorization header containing valid credentials for the proxy.