The HTTP status code 400 indicates that the server cannot or will not process the request due to a client error.
HTTP Status Code 400 - Bad Request:
Meaning: The server cannot process the request due to a client-side error. This could be due to malformed request syntax, invalid request message framing, or deceptive request routing.
Common Causes: Typical reasons for a 400 Bad Request include incorrect URL formatting, invalid query parameters, or unsupported characters in the request.
Client Error Category: Status codes in the 4xx range indicate client errors, where the problem lies with the request sent by the client rather than the server.
Other Status Codes:
100 - Continue: Informational status code indicating that the initial part of a request has been received and the client can continue with the rest of the request.
203 - Non-Authoritative Information: The server successfully processed the request, but the information may come from a different source.
303 - See Other: The server is redirecting the client to a different resource, typically using the GET method.
Reference:
HTTP Status Codes: MDN Web Docs
RFC 7231: HTTP/1.1 Semantics and Content