使用UCWA API向用户发送消息

Question

我会通过向客户端发送发布请求来尝试UCWA API。这是doc

应用初始化之后，我创建了我的请求。

const request = require('request-promise');
...

let URL= "https://************.lync.com"
let req= {
    url: URL + body.communication.startMessaging,
    method: 'POST',
    headers: {
        "Accept": "application/json; charset=utf-8",
        "authorization": "Bearer " + APP.Token
    },
    body: {
        importance:"Normal",
        sessionContext:"33dc0ef6-0570-4467-bb7e-49fcbea8e944",
        subject:"Sample Subject Line",
        telemetryId:null,
        to:"sip:hamza@opencircle.co",
        operationId:"5028e824-2268-4b14-9e59-1abad65ff393"
    },
    json:true
}
return new Promise((resolve,reject)=> {
    console.log(req);
    request(req).then(res=> {console.log("OK",res)},err=> console.log("ERRoR",err.message)).catch(err=>console.log("ERROR CATCH",err));
})

我收到此错误消息

  

'400-{“ code”：“ BadRequest”，“ subcode”：“ CallbackUriUnreachable”，“ message”：“类型\'PlatformService.Web.ValidationException \'的异常被抛出。”，“ debugInfo”：{ “ errorReportId”：“ a8034d8ad14c4b0695f7f78dc12c19fe”}}'