FAQ 보면서 경로를 확인했는데도 '템플릿 파일 'index.html'을(를) 찾을 수 없습니다' 가 출력됩니다.

뭘 잘못한 걸까요ㅠㅠ

from flask import Flask, render_template, request, jsonify
app = Flask(__name__)

import requests
from bs4 import BeautifulSoup

from pymongo import MongoClient
client = MongoClient('mongodb+srv://test:sparta@cluster0.gccri.mongodb.net/Cluster0?retryWrites=true&w=majority')
db = client.dbsparta

@app.route('/')
def home():
    return render_template('index.html')

@app.route("/movie", methods=["POST"])
def movie_post():
    url_receive = request.form['url_give']
    star_receive = request.form['star_give']
    comment_receive = request.form['comment_give']