bad request
With the Hypertext Transfer Protocol(HTTP), communication between the web browser and the web server takes place according to the request- response method. The browser makes a request to the web server via an existing TCP connection. The response from the web server contains an HTTP status code that provides information about the status of the connection.
If the input to a browser is incorrect, for example because the Internet address was misspelled or has changed, then the web server transmits an HTTP status code with a 400 digit and displays it on an error page.
In the case of an incorrectly entered Internet address( URL), the status code is 400, which means Bad Request or Bad File Request. This error message is transmitted even if there is the slightest deviation from the correct spelling.
This happens even if a lowercase letter is written instead of an uppercase letter or a backslash instead of a slash. In addition, HTTP status code 400 is transmitted if the website is not publicly accessible and protected by a password.