帮忙看看我写个http调用方法去调用推送接口，报错400请求错误，请问下具体是哪里设置的有问题?

请求接口是：https://api.jpush.cn/v3/push

请求参数是：{"notification":{"android":{"alert":"测试推送内容","extras":{"messageId":1564885843869380610},"title":"测试推送标题"}},"audience":{"registration_id":["120c83f760d98532fee"]},"message":{"msg_content":"测试推送内容","extras":{"messageId":1564885843869380610},"title":"测试推送标题"},"platform":["android"],"cid":"6ea693c5d59e8c3cab18469b48784eb9"}

按照registration_id来推送的。

appKey: 93fc7238d363a70824a59758
masterSecret: cab51a244c2a023e15954587

请求头部header中只是设置了Authorization，值是：Basic OTNmYzcyMzhkMzYzYTcwODI0YTU5NzU4OmNhYjUxYTI0NGMyYTAyM2UxNTk1NDU4Nw==
null