We got the error insufficient_security(71) in all connection to an FTPS, here is my log.
Why could be the error insufficient_security(71)
DEBUG [SecureSocket] 4 Feb 2025 13:25:44.884 : ChangeSecurityProtocol: Tls12, Tls13
DEBUG [SecureSocket] 4 Feb 2025 13:25:44.884 : Starting handshake
DEBUG [SocketController] 4 Feb 2025 13:25:44.884 : Starting TLS client
DEBUG [EdtTlsClient] 4 Feb 2025 13:25:44.915 : Supported client versions: TLS 1.3, TLS 1.2
DEBUG [EdtTlsClient] 4 Feb 2025 13:25:44.931 : Supported client cipher suites: TLS_AES_128_GCM_SHA256,TLS_AES_256_GCM_SHA384,TLS_CHACHA20_POLY1305_SHA256,TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,TLS_DHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_DHE_RSA_WITH_AES_128_CBC_SHA,TLS_DHE_RSA_WITH_AES_128_CBC_SHA256,TLS_DHE_RSA_WITH_AES_256_CBC_SHA,TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
ALL [SocketController] 4 Feb 2025 13:25:44.978 : Adding SendItem to to-send list
ALL [SocketController] 4 Feb 2025 13:25:44.978 : Removing SendItem from to-send list
DEBUG [SecureSocket] 4 Feb 2025 13:25:44.978 : Handshake started
DEBUG [SecureSocket] 4 Feb 2025 13:25:44.978 : Waiting for handshake completion
DEBUG [SecureSocket] 4 Feb 2025 13:25:44.978 : Waiting for handshake to complete (timeout=120000ms)
DEBUG [EdtTlsClient] 4 Feb 2025 13:25:44.994 : FTPConnection.2 Server version: TLS 1.2
DEBUG [EdtTlsClient] 4 Feb 2025 13:25:45.010 : FTPConnection.2 Selected cipher suite: TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 OnReceive - caught exception - closing
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 EnterpriseDT.BouncyCastle.Tls.TlsFatalAlert: insufficient_security(71)
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at EnterpriseDT.BouncyCastle.Tls.TlsDHUtilities.ReceiveDHConfig(TlsContext context, TlsDHGroupVerifier dhGroupVerifier, Stream input)
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at EnterpriseDT.BouncyCastle.Tls.TlsDheKeyExchange.ProcessServerKeyExchange(Stream input)
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at EnterpriseDT.BouncyCastle.Tls.TlsClientProtocol.HandleHandshakeMessage(Int16 type, HandshakeMessageInput buf)
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.dfUdv5dPaXf(ByteQueue )
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.vnfdvj2UYdA(Int16 , Byte[] , Int32 , Int32 )
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at gItj6odjbF42mSmgbnHQ.Vj4lUUdjt4qmjCuyaqB9.iNadjr882i0(Byte[] , Int32 , Int32 )
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.SafeReadFullRecord(Byte[] input, Int32 inputOff, Int32 inputLen)
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.OfferInput(Byte[] input, Int32 inputOff, Int32 inputLen)
ERROR [SocketController] 4 Feb 2025 13:26:15.144 : FTPConnection.2 at F8p4QdKMOseLR9WjbZk.kxiDQ9KfSGUBSoEUVIl.x7kKB9ra76(IAsyncResult )
DEBUG [SocketController] 4 Feb 2025 13:26:15.160 : FTPConnection.2 CloseConnection(e=insufficient_security(71))
DEBUG [SocketController] 4 Feb 2025 13:26:15.160 : FTPConnection.2 Shut down socket
DEBUG [SocketController] 4 Feb 2025 13:26:15.160 : FTPConnection.2 Closed socket
DEBUG [TransferBuffer] 4 Feb 2025 13:26:15.160 : FTPConnection.2 Close() called when open
DEBUG [SecureSocket] 4 Feb 2025 13:26:15.160 : FTPConnection.2 OnHandshakeComplete(False,insufficient_security(71))
DEBUG [SecureSocket] 4 Feb 2025 13:26:15.160 : FTPConnection.2 OnHandshakeComplete - waiting for lock
DEBUG [SecureSocket] 4 Feb 2025 13:26:15.160 : FTPConnection.2 OnHandshakeComplete - in lock
DEBUG [SecureSocket] 4 Feb 2025 13:26:15.160 : FTPConnection.2 OnHandshakeComplete - exiting lock
DEBUG [SecureSocket] 4 Feb 2025 13:26:15.160 : FTPConnection.2 OnHandshakeComplete - exit
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : Exception during handshake
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : EnterpriseDT.BouncyCastle.Tls.TlsFatalAlert: insufficient_security(71)
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at EnterpriseDT.BouncyCastle.Tls.TlsDHUtilities.ReceiveDHConfig(TlsContext context, TlsDHGroupVerifier dhGroupVerifier, Stream input)
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at EnterpriseDT.BouncyCastle.Tls.TlsDheKeyExchange.ProcessServerKeyExchange(Stream input)
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at EnterpriseDT.BouncyCastle.Tls.TlsClientProtocol.HandleHandshakeMessage(Int16 type, HandshakeMessageInput buf)
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.dfUdv5dPaXf(ByteQueue )
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.vnfdvj2UYdA(Int16 , Byte[] , Int32 , Int32 )
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at gItj6odjbF42mSmgbnHQ.Vj4lUUdjt4qmjCuyaqB9.iNadjr882i0(Byte[] , Int32 , Int32 )
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.SafeReadFullRecord(Byte[] input, Int32 inputOff, Int32 inputLen)
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at EnterpriseDT.BouncyCastle.Tls.TlsProtocol.OfferInput(Byte[] input, Int32 inputOff, Int32 inputLen)
ERROR [SecureSocket] 4 Feb 2025 13:26:15.160 : at F8p4QdKMOseLR9WjbZk.kxiDQ9KfSGUBSoEUVIl.x7kKB9ra76(IAsyncResult )
DEBUG [SecureSocket] 4 Feb 2025 14:36:27.673 : FTPConnection.2 Close()
