调试接口时，mark_all接口报500的错误，返回的是未知错误？这是服务器的问题吗？

msg: "未知错误"
success: false

请求和代码如下

http://localhost:8888/api/message/mark_all?needAccessToken=true

const axios = require('axios')
const queryString = require('query-string')

const baseUrl = 'http://cnodejs.org/api/v1'
module.exports = function (req, res, next) {
  const path = req.path
  const user = req.session.user || {}
  const needAccessToken = req.query.needAccessToken

  if(needAccessToken && !user.accessToken) {
    res.status(401).send({
      success: false,
      msg: 'need login'
    })
  }

  const query = Object.assign({}, req.query, {
    accesstoken: (needAccessToken && req.method === 'GET')? user.accessToken : ''
  })
  if (query.needAccessToken) delete query.needAccessToken

  axios(`${baseUrl}${path}`, {
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    },
    method: req.method,
    params: query,
    // 普通的对象，用queryString可以转为key=value的形式
    data: queryString.stringify(Object.assign({}, req.body, {
      accesstoken: (needAccessToken && req.method === 'POST')? user.accessToken : ''
    })),
  }).then(resp => {
    if(resp.status === 200) {
      res.send(resp.data)
    } else {
      res.status(resp.status).send(resp.data)
    }
  }).catch(err => {
    if(err.response) {
      res.status(500).send(err.response.data)
    } else {
      res.status(500).send({
        success: false,
        msg: '未知错误'
      })
    }
  })
}