400 error messages code example

Example 1: http status codes

Some important http status codes are:
200: The one you will mostly want to get. Succesful transfer
301: Moved Permanently. 300 defines Redirections
404: Not found. 400: bad requests as 401 Unauthorized and 403 Forbidden.
502: Bad Gateway. 500 defines Internal Server Errors.

Example 2: 200 error code

The HTTP 200 OK success status response code indicates that the request has succeeded. A 200 response is cacheable by default. The meaning of a success depends on the HTTP request method: GET : The resource has been fetched and is transmitted in the message body.

from developer.mozilla.org