通过代理的python sftp连接

Question

任何人都可以帮助我，尝试将文件上传到外部sftp。 我收到的错误消息是paramiko.ssh_exception.SSHException: Error reading SSH protocol banner。我尝试用谷歌搜索一些解决方案，但不幸的是，它们都没有用。

    target_host = 'your-experience-survey.com'
    target_port = 22
    target_username ='xx'
    target_password = 'xxxx'

    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    proxy =('proxyexample.com',80)
    sock.connect(proxy)
    target =(target_host, target_port)
    cmd_connect = ('CONNECT ' + target_host + ':' + str(target_port) +
        'HTTP/1.1\r\nProxy-Authorization: Basic ' +
        base64.b64encode('username:password'.encode()).decode() + '\r\n\r\n')        
    sock.sendall(cmd_connect.encode())

    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.connect(hostname=target_host,
                port=target_port,
                username=target_username,
                password=target_password,
                sock=sock)

    sftp = ssh.open_sftp()
    sftp.put(dataOutputPath + 'test.txt', iquoba_sftp + 'test.txt')

    ssh.close()