웹페이지를 찾을수없다고 뜨는데요. 뭐가문제일까요ㅠ

작성한 코드 및 에러 메세지

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

from pymongo import MongoClient
import certifi
ca = certifi.where()
client = MongoClient('mongodb+srv://test:sparta@cluster0.wt5djuw.mongodb.net/Cluster0?retryWrites=true&w=majority', tlsCAFile=ca)
db = client.dbsparta

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

@app.route("/mars", methods=["POST"])
def web_mars_post():
   name_receive = request.form['name_give']
   address_receive = request.form['address_give']
   size_receive = request.form['size_give']

   doc = {
       'name':name_receive,
       'address':address_receive,
       'size':size_receive
   }
   db.mars.insert_one(doc)

    return jsonify({'msg': '주문 완료!'})

@app.route("/mars", methods=["GET"])
def web_mars_get():
    return jsonify({'msg': 'GET 연결 완료!'})

if __name__ == '__main__':
   app.run('0.0.0.0', port=5000, debug=True)

ㅇ위에껀 app 이구

밑에껀 index 입니다.

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

from pymongo import MongoClient
import certifi
ca = certifi.where()
client = MongoClient('mongodb+srv://test:sparta@cluster0.wt5djuw.mongodb.net/Cluster0?retryWrites=true&w=majority', tlsCAFile=ca)
db = client.dbsparta

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

@app.route("/mars", methods=["POST"])
def web_mars_post():
   name_receive = request.form['name_give']
   address_receive = request.form['address_give']
   size_receive = request.form['size_give']

   doc = {
       'name':name_receive,
       'address':address_receive,
       'size':size_receive
   }
   db.mars.insert_one(doc)

    return jsonify({'msg': '주문 완료!'})

@app.route("/mars", methods=["GET"])
def web_mars_get():
    return jsonify({'msg': 'GET 연결 완료!'})

if __name__ == '__main__':
   app.run('0.0.0.0', port=5000, debug=True)