后端无法连接mongodb
我通过 Postman 测试，我的mongedb有数据
mongodb连接
它正常，如果测试/和发送“Hello World”，但当我测试/Data_Admin Postman发送[]回
这都是代码

// model

const mongoose = require("mongoose")
const Data_Admin_Shema = mongoose.Schema({
    id: {
        type: String,
        required : true
    },
    fullname: {
        type: String,
        required : true
    },
    lastname: {
        type: String,
        required : true
    },
    nick: {
        type: String,
        required : true
    },
    username: {
        type: String,
        required : true
    },
    password: {
        type: String,
        required : true
    },
    rank: {
        type: String,
        required : true
    },
})

exports.Data_Admin_Model = new mongoose.model("Data_Admin",Data_Admin_Shema)

// routes

const express = require("express")
const router = express.Router()
const {Data_Admin_Model} = require("../model/Data_Admin")

router.get("/",(req,res) => {
    res.send("Helo World")
})

router.get("/Data_Admin",async (req,res,next) => {
    Data_Admin_Model.find((err,Data_Admin) => {
        if (err) return next(err)
        res.json(Data_Admin)
    })
})

module.exports = router

// server

const express = require("express");
const cors = require("cors");

const mongoose = require('mongoose')

const app = express();

mongoose.set("strictQuery", false);

mongoose.connect('mongodb://127.0.0.1:27017/Data_since_Pro')
        .then(() => console.log('Yes app'))
        .catch((err) => console.error(err))

app.use(express.json())
app.use(cors());

const Data_Admin_Route = require("./routes/Data_Admins");

app.use("/",Data_Admin_Route);

app.listen(5000,() => console.log("app run"));

期望mongodb能够连接到后端。
我是初学者，如果这个问题对你们来说太简单了，对不起。