If the server got an issue with your request it can return 400 (Bad Request), which means that the server has received it successfully before acknowledging it as a bad one.
Even then, if the server returns 400 (Bad Request) the server can still attach a response body to that, in plain text/plain, application/octet-stream or even application/json, which could contain elaborate information.
Even then, if the server returns 400 (Bad Request) the server can still attach a response body to that, in plain text/plain, application/octet-stream or even application/json, which could contain elaborate information.