cspitzer wrote:

i actually got no error message except communication failed.

And that's indeed all WinSCP can tell.

i actually got no error message except communication failed.

I know that the number is present in the log. But did you get the number in any error message?

Btw, it's a sequence number of the message, not an error code.

2014-07-21 15:17:24.398 Type: SSH_FXP_OPEN, Size: 51, Number: 2051
< 2014-07-21 15:17:24.812 Type: SSH_FXP_STATUS, Size: 26, Number: 2051
< 2014-07-21 15:17:24.812 Status code: 4, [b]Message: 2051[/b], Server: Failure, Language: en

Can you show me an example of error message that you got from WinSCP with error 2051? I do not see any in the log.

I can see only:

Server sent disconnect message
type 11 (by application):
"ssh disconnect by application"

And that's the error you got from the server (on SSH protocol level).

In addition to that you received SFTP protocol level error:

Status code: 4, Message: 8451, Server: Failure

WinSCP chose to present you with SSH level error.

Neither of them is actually useful, but that's not WinSCP's fault.

Regarding SFTP status code 4, see:
https://winscp.net/eng/docs/sftp_codes#code_4

martin wrote:

Well, you server basically crashes the connection (seems like a bug to me, check your server's log). How can WinSCP tell why that happened to give you meaningful error message? It expects that the connection was lost (due to some networking failure) and retries. 5.5.x keeps retrying indefinitely, unless you limit it by Session.ReconnectTime. Since 5.6.x beta, default limit is 120 seconds.

sorry, i meant the server error message would have made diagnosis easier instead of just giving me error 2051.

Well, you server basically crashes the connection (seems like a bug to me, check your server's log). How can WinSCP tell why that happened to give you meaningful error message? It expects that the connection was lost (due to some networking failure) and retries. 5.5.x keeps retrying indefinitely, unless you limit it by Session.ReconnectTime. Since 5.6.x beta, default limit is 120 seconds.

i figured out this problem. the remote path didn't have a file name appended to it, so i was trying to upload a file on top of an existing directory. it would have helped if the returned error actually meant something.

i'm using this to great extent to a number of sites using your .Net interface. i just added in a new site to send files to, and the session.putfiles is hanging and never returning.

in looking at the debuglog, it has a set of these lines, once every second.

[2014-07-21 15:17:10.869Z] [0010] ExeSessionProcess.ProcessEvent entering
[2014-07-21 15:17:10.870Z] [0010] ExeSessionProcess.ProcessChoiceEvent entering
[2014-07-21 15:17:11.149Z] [000a] Opening log without write sharing
[2014-07-21 15:17:11.203Z] [000a] Opening log with write sharing
[2014-07-21 15:17:11.203Z] [000a] Log opened
[2014-07-21 15:17:11.203Z] [000a] Skipping 10 nodes
[2014-07-21 15:17:11.213Z] [000a] Closing log
[2014-07-21 15:17:11.213Z] [000a] Error parsing session log file, but it is not closed yet, will retry
[2014-07-21 15:17:11.213Z] [000a] Waiting for log update and dispatching events for 500
[2014-07-21 15:17:11.713Z] [000a] Opening log without write sharing
[2014-07-21 15:17:11.741Z] [000a] Opening log with write sharing
[2014-07-21 15:17:11.741Z] [000a] Log opened
[2014-07-21 15:17:11.741Z] [000a] Skipping 10 nodes
[2014-07-21 15:17:11.755Z] [000a] Closing log
[2014-07-21 15:17:11.756Z] [000a] Error parsing session log file, but it is not closed yet, will retry
[2014-07-21 15:17:11.756Z] [000a] Waiting for log update and dispatching events for 500
[2014-07-21 15:17:11.870Z] [0010] ExeSessionProcess.ProcessChoiceEvent leaving
[2014-07-21 15:17:11.870Z] [0010] ExeSessionProcess.ProcessEvent leaving

i can't seem to understand what it's trying to do now for this new site, nor why it is looping and not returning. The timeout also isn't making the looping stop.