{"error":{"code":400,"message":"CONFIGURATION_NOT_FOUND","errors":[{"message":"CONFIGURATION_NOT_FOUND","domain":"global","reason":"invalid"}]}}' code example

Example: { "error": { "code": 400, "message": "Required", "errors": [ { "message": "Required", "domain": "global", "reason": "required" } ] } }

Either you have forgot to pass required parameters or
You forgot to supply the `name` parameter in the URL. See the Simple upload 
documentation for more details.
Link : https://developers.google.com/storage/docs/json_api/v1/how-tos/upload#simple