Сервер + клиент на Python3, где ошибка?

import socket

HOST = 'localhost'
PORT = 7777
ADDR = (HOST, PORT)
server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server.bind(ADDR)

if __name__ == '__main__':
    try:
        while True:
            print('Waiting for data ...')
            d = server.recvfrom(1024)
            received = d[0]
            addr = d[1]
            print('Received data: ', received)
            print('From: ', addr)
            msg = input('Enter message to send: ')
            server.sendto(msg.encode('utf-8'), addr)
    except KeyboardInterrupt:
        pass
    finally:
        server.close()

import socket

HOST = 'localhost'
PORT = 7777

client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

if __name__ == '__main__':
    try:
        while True:
            msg = input('Enter message to send: ')
            client.sendto(msg.encode('utf-8'), (HOST, PORT))
            d = client.recvfrom(1024)
            reply = d[0]
            addr = d[1]
            print('Server reply: ' + reply.decode('utf-8'))
    except KeyboardInterrupt:
        pass
    finally:
        client.close()