Directory Listing Failure with proFTPD

Hello everyone.

I have installed and configured proFTPD on my DietPi distro, which is running on a RaspberryPi Zero attached to my local network. After managing to also configure TLS I tried to connect with my root account on it via FileZilla.

After running the aforementioned software in debug mode I got these logs.

esponse:	150 Opening BINARY mode data connection for file list
Trace:	CFtpRawTransferOpData::ParseResponse() in state 4
Trace:	CControlSocket::SendNextCommand()
Trace:	CFtpRawTransferOpData::Send() in state 5
Trace:	tls_layer_impl::on_read()
Trace:	tls_layer_impl::continue_handshake()
Trace:	TLS handshake: Received SERVER HELLO
Trace:	TLS handshake: Processed SERVER HELLO
Trace:	TLS handshake: Received ENCRYPTED EXTENSIONS
Trace:	TLS handshake: Processed ENCRYPTED EXTENSIONS
Trace:	TLS handshake: Received FINISHED
Trace:	TLS handshake: Processed FINISHED
Trace:	TLS handshake: About to send FINISHED
Trace:	TLS handshake: Sent FINISHED
Trace:	TLS Handshake successful
Trace:	TLS Session resumed
Trace:	Protocol: TLS1.3, Key exchange: ECDHE-PSK, Cipher: AES-256-GCM, MAC: AEAD
Trace:	tls_layer_impl::verify_certificate()
Trace:	CTransferSocket::OnConnect
Trace:	CTransferSocket::OnReceive(), m_transferMode=0
Trace:	tls_layer_impl::on_read()
Trace:	CTransferSocket::OnReceive(), m_transferMode=0
Trace:	TLS handshake: Received NEW SESSION TICKET
Trace:	TLS handshake: Processed NEW SESSION TICKET
Trace:	gnutls_record_recv returned spurious EAGAIN
Trace:	tls_layer_impl::on_read()
Trace:	tls_layer_impl::on_read()
Trace:	CFtpControlSocket::OnReceive()
Response:	425 Unable to build data connection: Operation not permitted
Trace:	CFtpRawTransferOpData::ParseResponse() in state 5
Trace:	CFtpControlSocket::ResetOperation(2)
Trace:	CControlSocket::ResetOperation(2)
Trace:	CFtpRawTransferOpData::Reset(2) in state 5
Trace:	CFtpListOpData::SubcommandResult(2) in state 3
Trace:	CFtpControlSocket::ResetOperation(2)
Trace:	CControlSocket::ResetOperation(2)
Trace:	CFtpListOpData::Reset(2) in state 3
Error:	Failed to retrieve directory listing
Trace:	CFileZillaEnginePrivate::ResetOperation(2)
Response:	450 LIST: Operation not permitted
Trace:	Unexpected reply, no reply was pending.

What could be the problem here?

Thank you in advance

I found following on Filezilla forum. Does it fit your issue?