getting internal Server error and empty Object - node.js

Question

made an API for Social media Application to get timeline posts on the app, I requested from Thunder Client
request query is like: http://localhost:8000/post/63d4051a252ef6c3d50d7f17/timeline, where userId is this :63d4051a252ef6c3d50d7f17,
i did log userId and correctly got Data Document from mongoDB
try {
const currentUserPost = await PostModel.find({ userId: userId });
console.log( currentUserPost )
}
but still getting empty object {} error is: Internal server error status code 500 on thunder client,
check out once below code, and let me know what's wrong and why. it seems good to me but it isn't working.
PostControler.js
const PostModel = require("../Models/Postmodels");
const mongoose = require("mongoose");
const UserModel = require("../Models/Usermodel");
/ get timeLine post
const getTimeLinePost = async (req, res) => {
const userId = req.params.id;
try {
const currentUserPost = await PostModel.find({ userId: userId });
console.log( currentUserPost )
const followingPost = await UserModel.aggregate([
{
$match: {
_id: new mongoose.Types.ObjectId(userId),
}
},
{
$lookup: {
from: "posts",
localField: "following",
foreignField: "userId",
as: "followingPosts",
}
},
{
$project: {
followingPost: 1,
_id: 0,
}
},
]);
res.status(200).json(currentUserPost.concat(...followingPost[0].followingPost)
.sort((a,b)=>{
return b.createdAt - a.createdAt
}));
} catch (error) {
res.status(500).send(error);
}
};
module.exports = { createPost,getPost, updatePost, deletePost, likesDislikesPost, getTimeLinePost };
PostRoute.js
const express = require("express");
const {createPost,getPost, updatePost, deletePost, likesDislikesPost, getTimeLinePost} = require("../Controller/PostControler");
const router = express.Router();
router.post('/', createPost)
router.get('/:id', getPost)
router.put('/:id', updatePost)
router.delete('/:id', deletePost)
router.put('/:id/like', likesDislikesPost)
router.get('/:id/timeline', getTimeLinePost)
module.exports = router
index.js
const express = require("express")
require('dotenv').config()
const bodyparser = require("body-parser")
const mongoose = require("mongoose")
const app = express();
const Authroute = require("./Routes/Authroute")
const UserRoute = require("./Routes/userRout")
const PostRout = require("./Routes/PostRoute")
.
.
.
.
.
.
app.use("/auth",Authroute)
app.use("/user",UserRoute)
app.use("/post", PostRout)