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406 Not Acceptable

The HTTP 406 Not Acceptable status code indicates that the server cannot provide a response matching the formats requested by the client.

Published 16 Jul 2026 · HTTP Status Code

What is HTTP 406 Not Acceptable?

The 406 Not Acceptable response occurs when the server cannot generate a representation that matches the client requirements.

Clients communicate supported formats using the Accept header.

Accept: application/xml

406 Not Acceptable means the server cannot satisfy the client's requested response format.

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The HTTP 407 Proxy Authentication Required status code indicates that authentication is required with a proxy server.

The HTTP 408 Request Timeout status code indicates that the server timed out waiting for the client request.

The HTTP 409 Conflict status code indicates that a request conflicts with the current state of the resource.