not found Error while running a flask app

[venkatmanish]

import datetime
import hashlib
import json
from flask import Flask, jsonify

class Blockchain:
    def __init__(self):
        self.chain = []
        self.create_block(proof=1, previous_hash='0')
    def create_block(self, proof, previous_hash):
        block = {'index' : len(self.chain) + 1,
                 'timestamp' : str(datetime.datetime.now()),
                 'proof' : proof,
                 'previous_hash' : previous_hash}
        self.chain.append(block)
        return block
    def get_previous_block(self):
        return self.chain[-1]
    def proof_of_work(self,previous_proof):
        proof = 1
        check_proof = False
        while check_proof is False:
            hash_operation = hashlib.sha256(str(proof**3-previous_proof**3).encode()).hexdigest()
            if hash_operation[:4] == '0000':
                check_proof = True
            else:
                proof +=1
        return proof
    def hash(self, block):
        encoded_block = json.dumps(block , sort_keys = True).encode()
        return hashlib.sha256(encoded_block).hexdigest()
    def is_chain_valid(self, chain):
        previous_block = chain[0]
        block_index = 1
        while block_index < len(chain):
            block = chain[block_index]
            if block['previous_hash'] != self.hash(previous_block):
                return False
            previous_proof = previous_block['proof']
            proof = block['proof']
            hash_operation = hashlib.sha256(str(proof**3-previous_proof**3).encode()).hexdigest()
            if hash_operation[:4]!='0000':
                return False
            prevous_block = block
            block_index += 1
            
            
#web app using flask
app = Flask(__name__)
#creating a blockchain
blockchain = Blockchain()
#mining a new block
@app.route('/mine_block', methods = [ 'GET' ])
def mine_block():
    previous_block = blockchain.get_previous_block()
    previous_proof = previous_block['proof']
    proof = blockchain.proof_of_work(previous_proof)
    previous_hash = blockchain.hash(previous_block)
    block = blockchain.create_block(proof, previous_hash)
    response = {'message':'Congratulations, you just mined a block!',
                'index': block['index'],
                'timestamp': block[ 'timestamp'],
                'proof':block['proof'],
                'previous_hash':block['previous_hash']}
    return jsonify(response), 200

@app.route('/get_chain', methods = [ 'GET' ])
def get_chain():
    response = {'chain':blockchain.chain,
                'length':len(blockchain.chain)}
    return jsonify(response), 200
#running
app.run(host='0.0.0.0' , port = 5050)

//error
Not Found

The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.can anyone help me to run this

i tried running the flask app many times by changing the port numbers but it still shows not found i am expecting that if anyone could resolve this issue on app.run()[tag:flask app]

[davidism]

You need to navigate to one of the paths you defined, you didn't set anything for the root.

[venkatmanish]

can you please tell how to do that