A 406 error code typically indicates that the server is unable to provide the requested content in the format that the client has specified in the request's "Accept" header. This means that the server has received the request but cannot fulfill it because the client's browser or device is requesting a format that the server cannot provide.
For example, if a client sends a request with an "Accept" header specifying that it only wants JSON data, but the server can only provide XML data, the server will respond with a 406 error code.
To resolve this issue, the client can either modify its "Accept" header to request a format that the server can provide, or the server can be configured to support the requested format.