Fatal error 'UnknownCa' has been reported by the remote connection end.

Question

Hi, I try to connect remote FTPS connection with implicit SSL . using FTP over SSL library but I get a problem right now.
It seems that error comes from remote server and server do not accept my client certificate. Actually I connected remote and transferred files with CuteFTP program but I can not succeeded with c# code.

Log:

2016-02-25 14:35:11.908 Opening log file.
2016-02-25 14:35:11.908 Using FileLogWriter version 2.0.5885.0.
2016-02-25 14:35:14.325 INFO Ftp(1)[8] Info: Connecting to 62.XXX.XXX.98:990 using Ftp 4.0.5885.0 (trial version).
2016-02-25 14:35:14.337 INFO Ftp(1)[8] Info: Using proxy none.
2016-02-25 14:35:14.367 DEBUG Ftp(1)[8] Info: Connection succeeded.
2016-02-25 14:35:14.372 DEBUG Ftp(1)[8] Info: Upgrading control connection to TLS/SSL.
2016-02-25 14:35:14.397 INFO Ftp(1)[8] TLS: State StateChange:Negotiating
2016-02-25 14:35:14.397 DEBUG Ftp(1)[8] TLS: HandshakeMessage:ClientHello was sent.
2016-02-25 14:35:14.418 DEBUG Ftp(1)[8] TLS: HandshakeMessage:ServerHello was received.
2016-02-25 14:35:14.419 INFO Ftp(1)[8] TLS: Client requested TLS 1.2, server is asking for TLS 1.0.
2016-02-25 14:35:14.421 DEBUG Ftp(1)[8] TLS: HandshakeMessage:Certificate was received.
2016-02-25 14:35:14.422 DEBUG Ftp(1)[8] TLS: HandshakeMessage:CertificateRequest was received.
2016-02-25 14:35:14.422 DEBUG Ftp(1)[8] TLS: HandshakeMessage:ServerHelloDone was received.
2016-02-25 14:35:14.424 DEBUG Ftp(1)[8] TLS: Verifying server certificate ('E=destek@xxx.com.tr, S=TR, O=BKM, OU=FTP, L=Istanbul, CN=sftp.xxx.com.tr, C=TR').
2016-02-25 14:35:14.426 DEBUG Ftp(1)[8] TLS: Certificate verification result: Accept
2016-02-25 14:35:14.430 DEBUG Ftp(1)[8] TLS: Client certificate authentication was requested.
2016-02-25 14:35:14.431 DEBUG Ftp(1)[8] TLS: Suitable client certificate is available ('CN=http://www.xxxx.com/tr/xxxx/, OU=xxx  Services Analysis&Software, O=xxx xxxx xxxx xxxx, L=Eyup, S=Istanbul, C=TR').
2016-02-25 14:35:14.432 DEBUG Ftp(1)[8] TLS: HandshakeMessage:Certificate was sent.
2016-02-25 14:35:14.433 DEBUG Ftp(1)[8] TLS: HandshakeMessage:ClientKeyExchange was sent.
2016-02-25 14:35:14.447 INFO Ftp(1)[8] TLS: Performing client certificate authentication.
2016-02-25 14:35:14.469 DEBUG Ftp(1)[8] TLS: HandshakeMessage:CertificateVerify was sent.
2016-02-25 14:35:14.470 DEBUG Ftp(1)[8] TLS: CipherSpec:ChangeCipherSpec was sent.
2016-02-25 14:35:14.470 DEBUG Ftp(1)[8] TLS: HandshakeMessage:Finished was sent.
2016-02-25 14:35:14.473 INFO Ftp(1)[8] TLS: Alert Alert:Alert was received.
2016-02-25 14:35:14.514 DEBUG Ftp(1)[8] TLS: Error while processing TLS packet: Rebex.Net.TlsException: Fatal error 'UnknownCa' has been reported by the remote connection end.
   at Rebex.Net.WAI.XR(Byte[] U, Int32 W, Int32 R)
   at Rebex.Net.UAI.PP(Byte[] U, Int32 W, Int32 R)
   at Rebex.Net.UAI.OP()
2016-02-25 14:35:14.516 INFO Ftp(1)[8] TLS: Alert Alert:Alert was sent.
2016-02-25 14:35:14.516 INFO Ftp(1)[8] TLS: State StateChange:Closed
2016-02-25 14:35:14.578 DEBUG Ftp(1)[8] TLS: Closing TLS socket.
2016-02-25 14:35:14.649 ERROR Ftp(1)[8] Info: Rebex.Net.TlsException: Fatal error 'UnknownCa' has been reported by the remote connection end. ---> Rebex.Net.TlsException: Fatal error 'UnknownCa' has been reported by the remote connection end. ---> Rebex.Net.TlsException: Fatal error 'UnknownCa' has been reported by the remote connection end. ---> Rebex.Net.TlsException: Fatal error 'UnknownCa' has been reported by the remote connection end.
   at Rebex.Net.WAI.XR(Byte[] U, Int32 W, Int32 R)
   at Rebex.Net.UAI.PP(Byte[] U, Int32 W, Int32 R)
   at Rebex.Net.UAI.OP()
   --- End of inner exception stack trace ---
   at Rebex.Net.UAI.OP()
   at Rebex.Net.UAI.JP()
   at Rebex.Net.TlsSocket.Negotiate()
   at Rebex.Net.QCI.EW(TlsParameters U)
   at Rebex.Net.Ftp.AX(String U, Int32 W, TlsParameters R, SslMode I, FtpSecureUpgradeType Q)
   --- End of inner exception stack trace ---
   at Rebex.Net.Ftp.AX(String U, Int32 W, TlsParameters R, SslMode I, FtpSecureUpgradeType Q)
   --- End of inner exception stack trace ---
   at Rebex.Net.Ftp.AX(String U, Int32 W, TlsParameters R, SslMode I, FtpSecureUpgradeType Q)

My Code :

Ftp ftp = new Ftp();
string certPath = @"C:\Users\xxx\Desktop\CertRebex.pfx";

CertificateChain certificateChain = CertificateChain.LoadPfx(certPath, "abcd.1234");

ftp.Settings.SslClientCertificateRequestHandler = CertificateRequestHandler.CreateRequestHandler(certificateChain);

ftp.Settings.SslAcceptAllCertificates = true;

string ftpUri = @"ftp://62.XXX.XXX.98:990/0900";

ftp.LogWriter = new Rebex.FileLogWriter(@"C:\Users\xxx\Desktop\Rebexlog.txt", Rebex.LogLevel.Debug);

// Connect securely using explicit SSL.
ftp.Connect(ftpUri, 990, SslMode.Implicit);

ftp.Login(UserName, Password);

Answer 1

I solved the problem. I must be sure that my certificate comes from right CA.

Comments

Yes, this is what the "Unknown CA" server error means. Unknown certificate authority. Thanks for posting back.