4xx Client Error
HTTP 406 Not Acceptable
The server cannot produce a response matching the client's Accept headers.
Check a URL's HTTP statusWhat 406 means
Content negotiation failed: the client asked for a format or language the server cannot provide.
Common causes
- An Accept header requests an unsupported format.
- Some security modules return 406 for blocked requests.
How to fix it
- Send a broader Accept header such as */*.
- Review server security module logs.
How to check a status code
Enter a URL in the HTTP Status Checker to see its status code, every redirect hop, and response time. For redirect-heavy pages, the Website Speed Test shows how much time redirects add.
FAQ
- What does HTTP 406 mean?
- 406 Not Acceptable is a 4xx client error status code. The server cannot produce a response matching the client's Accept headers.
- What causes a 406 error?
- An Accept header requests an unsupported format. Some security modules return 406 for blocked requests.
- How do I fix HTTP 406?
- Send a broader Accept header such as */*. Review server security module logs.
Defined in RFC 9110.
Other 4xx client error codes
400 Bad Request401 Unauthorized403 Forbidden404 Not Found405 Method Not Allowed408 Request Timeout409 Conflict410 Gone413 Content Too Large414 URI Too Long415 Unsupported Media Type418 I'm a teapot422 Unprocessable Content425 Too Early429 Too Many Requests431 Request Header Fields Too Large451 Unavailable For Legal Reasons