What does HTTP 406 Not Acceptable mean?

The HyperText Transfer Protocol (HTTP) 406 Not Acceptable client error response code indicates that the server cannot produce a response matching the list of acceptable values defined in the request’s proactive content negotiation headers, and that the server is unwilling to supply a default representation.

For More Information Please Refer: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/406