EdtFTPNetPro FTPS 命令 PBSZ 0 导致问题

如何解决EdtFTPNetPro FTPS 命令 PBSZ 0 导致问题

使用 edtFTPnet/PRO 库连接到 FTPS 服务器。

public void Run(string serverAddress,int serverPort,string userName,string password)
{
    ftpConnection.ServerAddress = serverAddress;
    ftpConnection.ServerPort = serverPort; 
    ftpConnection.UserName = userName;
    ftpConnection.Password = password;

    // select explicit FTPS
    ftpConnection.Protocol = FileTransferProtocol.FTPSExplicit;

    // switch off server validation (unsafe - only do this when testing)
    ftpConnection.ServerValidation = SecureFTPServerValidationType.None;
    ftpConnection.MinSSLVersion = SSLFTPSSLVersion.TLS12;
    
    // connect to server
    ftpConnection.Connect();

    // get the current working directory and files
    ftpConnection.GetFiles();

    ftpConnection.Close();
}

但是，当 lib 发送 PBSZ 0 命令时，服务器以 502 响应：

Reply: 220-Welcome
Reply: 220
Command: --->AUTH TLS
Reply: 234 SSL/TLS enabled...start negotiation
...
[Debug]: Synchronous handshake complete
[Debug]: Tls1,Tls11,Tls12 handshake complete.
Command: --->PBSZ 0
Reply: 502 Command unkNown,not supported or not allowed...
[Debug]: Expected reply codes = [200,235](strict=False)
[Debug]: Purging task queue
[Debug]: Closing connection [instance=19,abrupt=False]
Command: --->QUIT
Reply: 221-
Reply: 221 Goodbye

如果我从 FileZilla 打开到同一个 FTP 服务器的另一个连接，我会看到以下内容：

Status: Connection established,waiting for welcome message...
Trace:  CFtpControlSocket::OnReceive()
Response:   220-Welcome
Response:   220
...
Command:    AUTH TLS
Trace:  CFtpControlSocket::OnReceive()
Response:   234 SSL/TLS enabled... start negotiation
Trace:  CFtplogonopData::ParseResponse() in state 2
Status: Initializing TLS...
Trace:  tls_layer_impl::client_handshake()
...
Status: Verifying certificate...
Trace:  CFtpControlSocket::SetAsyncRequestReply
Status: TLS connection established.
...
Command:    PBSZ 0
Trace:  tls_layer_impl::on_read()
Trace:  CFtpControlSocket::OnReceive()
Response:   200 PBSZ set to PBSZ 0

导致服务器响应 502 并向 FileZilla 客户端响应 200 的 C# 代码中缺少什么？