https://msgapi.umeng.com/api/send 报400

地址：https://msgapi.umeng.com/api/send?sign=323eb2e0f8d5a4fab78b2bbe6fb4faf3
参数：{"appkey":"5ba3129fb465f56b00000084","timestamp":1767851077339,"type":"customizedcast","device_tokens":"","alias_type":"edz","alias":"P15879513257FH","file_id":"","filter":{},"payload":{"display_type":"notification","body":{"ticker":"您有一条新消息","ticke":"您有一条新消息","title":"会员消费","text":"郭购买了1.00件商品，总金额¥35.00","after_open":"go_custom","url":"","activity":"","custom":"{\"clientcode\":\"Y0070\",\"examplecode\":\"IhEhQgKNz7v43gJKlH8HM9%2b4hGSvFjCinNIk8b5tOZo%3d\",\"fromcode\":\"\",\"msgtype\":\"sale\",\"type\":\"\"}"},"extra":{"key1":"value1","key2":"value2"}},"description":"会员动态消息","mipush":true,"mi_activity":"com.cinapaod.shoppingguide_new.upush.UPushActivity"}

有大神能支持一下吗