415
SIP
415 Unsupported Media Type
The server is refusing the request because the message body is in a format not supported by the server for the requested method.
On this page
When You See This Code
When the Content-Type of the request body is not supported. For INVITE, this often means an unsupported SDP format.
How to Fix
Check the Accept header in the response to see supported media types. Use a compatible Content-Type in your request.
Specification
Cross-Protocol Equivalents
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
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WebRTC Signaling with SIP and WebSocket
Real-Time Protocols
RFC 3261: SIP Protocol Deep Dive
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TLS 1.3: Faster, Simpler, More Secure
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Frequently Asked Questions
What is SIP 415 Unsupported Media Type?
The server is refusing the request because the message body is in a format not supported by the server for the requested method.
When do you see SIP 415 Unsupported Media Type?
When the Content-Type of the request body is not supported. For INVITE, this often means an unsupported SDP format.
How to fix SIP 415 Unsupported Media Type?
Check the Accept header in the response to see supported media types. Use a compatible Content-Type in your request.