A “400 Bad request” error happens when the web server (running the website) thinks that the data stream sent by the client (e.g. your web browser) was “malformed” i.e. did not respect the HTTP protocol completely. So the Web server was unable to understand the request and process it. This might happen when URLs are handed-off to a servlet engine where no default document or servlet is configured, or the where HTTP request method is not implemented.
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