jsch Auth Fail errors

We have a major issue that still can’t be figured out. We are on WM 9.12 on linux and we have one vendor and one vendor only that we are having intermittent “Auth Fail” errors with when we try to send files to their SFTP server. We do occasionally get in, but it could be hours later and we have even had situations where a day or so would pass before we could connect.

We have the vendor’s information setup under Settings/SFTP on IS Admin screen. The user alias authentication type is Password (not Public Key) by the vendor’s request.

The vendor has said multiple times that the issue is not on their end and nothing has changed on their side, so although I believe it has to be on their end, I can’t prove it.

Can anyone provide any tips on investigating this? Is there logging somewhere that can perhaps be increased that can possibly show what is going on? I have SFTP logging set to Trace and I don’t see anything helpful in the server log. Is there something specific on the vendor’s SFTP server that I can ask them to check? As mentioned earlier, we do sometimes get in, so I seriously doubt the issue is the password. We don’t have this issue with ANYBODY else, so this is really odd.

Today, I couldn’t even log into their server from the Linux command prompt utilizing sftp -oPort=22 user@servername , but by some miracle, 10 minutes after trying that, we were able to connect after over 7 hours of “Auth fail” errors, maybe 30 seconds later after that, I try a Test under Settings/SFTP/User Alias Settings on IS admin screen and again “Auth Fail”…what in the world is going on? Please help as this is frustrating everybody over here.


Enable jsch handshake logging by settin watt.ssh.jsch.logging=true, this will give you idea on what all the KEX ciphers getting selected during handshake or at what step the authentication is failing. The handshake logs will added in wrapper.log file.



please check if you have the latest Fixes applied for your IS as there were some issues fixed w.r.t. to SFTP/Jsch-Lib.