Error: Transport endpoint is not connected (Python Sockets)

Question

I'm trying to create a simple chat application using sockets in Python (with threads). Application is simple client has to threads one to send data and another to receive. Server has to two threads one to accept client connection and another to broadcast the message. But on running the below code, I'm getting error message

Transport endpoint is not connected

Can anybody tell me why I'm getting this error

Client

import socket, threading

def send():
    msg = raw_input('Me > ')
    cli_sock.send(msg)

def receive():
    data = cli_sock.recv(4096)
    print('> '+ str(data))

if __name__ == "__main__":   
    # socket
    cli_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    # connect
    HOST = 'localhost'
    PORT = 5028
    cli_sock.connect((HOST, PORT))     
    print('Connected to remote host...')

    thread_send = threading.Thread(target = send)
    thread_send.start()

    thread_receive = threading.Thread(target = receive)
    thread_receive.start()

Server

import socket, threading

def accept_client():
    while True:
        #accept    
        cli_sock, cli_add = ser_sock.accept()
        CONNECTION_LIST.append(cli_sock)
        print('Client (%s, %s) connected' % cli_add)

def broadcast_data():
    while True:
        data = ser_sock.recv(4096)
        for csock in CONNECTION_LIST:
            try:
                csock.send(data)
            except Exception as x:
                print(x.message)
                cli_sock.close()
                CONNECTION_LIST.remove(cli_sock)

if __name__ == "__main__":    
    CONNECTION_LIST = []

    # socket
    ser_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    # bind
    HOST = 'localhost'
    PORT = 5028
    ser_sock.bind((HOST, PORT))

    # listen        
    ser_sock.listen(1)
    print('Chat server started on port : ' + str(PORT))

    thread_ac = threading.Thread(target = accept_client)
    thread_ac.start()

    thread_bd = threading.Thread(target = broadcast_data)
    thread_bd.start()

Solution

You're using server sockets incorrectly. You cannot recv on server sockets, instead you accept connections on them; accept returns the actual connection socket:

ser_sock.listen(1)
sock, addr = ser_sock.accept()

print('Got connection from {}'.format(addr))

# only this *connection* socket can receive!
data = sock.recv(4096)