416
SIP
416 Unsupported URI Scheme
The server cannot process the request because the URI scheme in the Request-URI is unknown to the server.
On this page
When You See This Code
When using a URI scheme (e.g., tel:, im:, pres:) that the receiving server does not support.
How to Fix
Use a supported URI scheme. Most SIP servers support sip: and sips: schemes. Check server capabilities with OPTIONS.
Specification
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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PBX (Private Branch Exchange)
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TLS Versions
Frequently Asked Questions
What is SIP 416 Unsupported URI Scheme?
The server cannot process the request because the URI scheme in the Request-URI is unknown to the server.
When do you see SIP 416 Unsupported URI Scheme?
When using a URI scheme (e.g., tel:, im:, pres:) that the receiving server does not support.
How to fix SIP 416 Unsupported URI Scheme?
Use a supported URI scheme. Most SIP servers support sip: and sips: schemes. Check server capabilities with OPTIONS.