MongoDB创建新用户时触发Error code 8000问题求助

我是MongoDB新手，存在术语盲区，排查问题时遇到困难。我搭建了一个简单的认证接口，数据库连接显示成功，但用Postman创建新用户时，每次都会触发500错误：

{
    "message": "Error creating user",
    "error": {
        "ok": 0,
        "code": 8000,
        "codeName": "AtlasError",
        "name": "MongoError"
    }
}

这个错误信息指向性不强，我试过谷歌搜索、查阅MongoDB文档，都没找到有效的排查方向。不确定问题出在代码还是MongoDB集群配置，但更倾向于集群设置问题（这部分我最陌生）。错误触发在app.js的register接口中user.save()的catch逻辑里。

相关代码片段如下：

.env文件（密码已隐藏） #

DB_URL=mongodb+srv://emc_admin-prime:[PASSWORD]@cluster1.9ifxogd.mongodb.net/?retryWrites=true&w=majority

dbConnect.js #

const mongoose = require("mongoose");
require('dotenv').config()

async function dbConnect() {
  mongoose
    .connect(
        process.env.DB_URL,
      {
        useNewUrlParser: true,
        useUnifiedTopology: true,
      }
    )
    .then(() => {
      console.log("Successfully connected to MongoDB Atlas!");
    })
    .catch((error) => {
      console.log("Unable to connect to MongoDB Atlas!");
      console.error(error);
    });
}

module.exports = dbConnect;

userModel.js #

const mongoose = require("mongoose");

const UserSchema = new mongoose.Schema({
  email: {
    type: String,
    required: [true, "Please provide an Email!"],
    unique: [true, "Email Exist"],
  },

  password: {
    type: String,
    required: [true, "Please provide a password!"],
    unique: false,
  },
});

module.exports = mongoose.model.Users || mongoose.model("Users", UserSchema);

app.js #

const express = require("express");
const app = express();
const bcrypt = require('bcrypt');
const bodyParser = require('body-parser');
const dbConnect = require('./db/dbConnect');
const User = require('./db/userModel');

dbConnect();

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.get('/', (request, response, next) => {
  response.json({ message: 'Server response' });
  next();
});

app.post('/register', (request, response) => {
  bcrypt.hash(request.body.password, 10)
    .then((hashedPassword) => {
      const user = new User({
        email: request.body.email,
        password: hashedPassword,
      });

      user
        .save()
        .then((result) => {
          response.status(201).send({
            message: 'User created successfully',
            result,
          });
        })
        .catch((error) => {
          response.status(500).send({
            message: 'Error creating user',
            error,
          });
        });
    })
    .catch((error) => {
      response.status(500).send({
        message: 'Password was not hashed successfully',
        error,
      });
    });
});

module.exports = app;

排查方向需求 #

希望能得到以下方向的排查建议，不要直接给出答案：

• MongoDB Atlas集群配置层面的排查要点
• 代码中可能被忽略的细节排查方向
• 如何获取更详细的错误日志来定位问题

内容的提问来源于stack exchange，提问作者tganyan