400 BAD request HTTP error code meaning? - Stack Overflow
https://stackoverflow.com/questions/19671317/400-bad-request-http-error-code-meaning
WEBOct 30, 2013 · A 400 means that the request was malformed. In other words, the data stream sent by the client to the server didn't follow the rules. In the case of a REST API with a JSON payload, 400's are typically, and correctly I would say, used to indicate that the JSON is invalid in some way according to the API specification for the service.
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