The node middle layer requests the back-end service. Why can't await get the data from the request-promise-native module?

use node as the middle layer request server, please spray gently. The project is as follows:

node version 8.11.2, using koa2 version 2.5.1
because the node server is needed to request the backend api, the request module is used
uses the koa2-cors package (2.0.5) for cross-domain processing
uses koa-router (7.1.1)

// login
const request = require("request")
router.post("/login", async (ctx, next) => {
  ctx.body = {  // 
    code: 200,
    msg: "success"
   }  
})
// 
router.post("/login", async (ctx, next) => {
    // 
    
   // api 
    request({
    url: "http://xx.55.41.71:9090/tokens",
    method: "POST",
    json: true,
    headers: {
      "content-type": "application/json",
    },
    body: JSON.stringify({
      "userName": "xxxxxx",
      "password": "xxxxxx"
    })
  }, function (error, response, body) {
    if (!error && response.statusCode == 200) {
      console.log(body)  // 
      ctx.body = body  //  request-promise-native
    }
  })
    
})

for more information about the above, please refer to the link

problem description

//requestrequest-promise-native
// const request = require("request")  // request  
// request-promise-nativenpminstall requese --save 
// demorequire("requese") npm install requese --save 
 const request = require("request-promise-native")
// 
let res = await request({
    url: "http://120.55.41.71:9090/tokens",
    method: "POST",
    headers: {
      "content-type": "application/json",
    },
    body: JSON.stringify({
      "userName": ctx.request.body.name,
      "password": ctx.request.body.password
    })
  })
  ctx.body = res

node reports an error as follows

because the time is relatively late, I am not sure that the error in the backend has caused my error (because I just found a problem with the postman call but I am not sure), so I feel that my node has made a mistake.
I want a big god to say what the mistake is? It is best to give a demo example of request-promise-native, look at the official documents of github, and have little knowledge of it in English. Look at the official request-promise (it seems to need the support of another plug-in), request-promise-native (native implementation, can not be used) request-promise-any (it seems to need a support, too). Which of these works well?

router.post('/login', async (ctx, next) => { const options = { url: 'http://xx.55.41.71:9090/tokens', method: "POST", json: true, headers: { "content-type": "application/json", }, body: JSON.stringify({ 'userName': 'xxxxxx', 'password': 'xxxxxx' }) }; ctx.body = await requestPromise(options); }); // promise function requestPromise (options) { return new Promise((resolve, reject) => { request(options, (error, response, body) => { if (error) { reject(error); } resolve(body); }) }) }

const util = require('util'); const request = require('request'); const requestPromise = util.promisify(request); router.post('/login', async (ctx, next) => { const options = { url: 'http://xx.55.41.71:9090/tokens', method: "POST", json: true, headers: { "content-type": "application/json", }, body: JSON.stringify({ 'userName': 'xxxxxx', 'password': 'xxxxxx' }) }; const {response, body} = await requestPromise(options); ctx.body = body; });