Thanks for your feedback.

Hello Martin
problem is isolated and can be solved by ourselves.
It is due to an incorrectly configured firewall.
Actually we don't know why other application doesn't have that failure.

Thanks for your brillant support. Without your help no one had a deeper look to the firewall configuration. Everybody said it can't be a problem when other applications function as exprected.

Hello Martin
mail is sent to you

Can you send me an email, so I can send you back a debug version of WinSCP to track the problem? Please include a link back to this topic in your email. Also note in this topic that you have sent the email. Thanks.

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Regarding the test account: I do not need to access any real data. A chrooted account with some random file should be enough.

Sorry no test account possible.

I attached the logging file from the new version.
Sorry the FTP isn't under my control and the data there are under EU-GDPR so I think I can't get a test account. I will try but I don't think it will be successful.

Please post log from the latest version of WinSCP (in English if possible).
Any chance of getting a test account on your server?

Hello Martin
unfortunately no
I tried the portable version 6.2.2
but I get the same error.
perhaps a little additional information
the file is created as a zero byte file and can be deleted after the error message.

Thanks. Can you try it with the latest beta version?
https://winscp.net/eng/download.php

Here are my log files from FileZilla and WinSCP.
Thanks for investigation.
Marcus

Please post log files both from WinSCP and FileZilla.

When I try to upload a file to a FTP Server with explicit TLS/SSL then I get an error that a Client certificate is needed. When I try that with other FTP Clients like FileZilla everything is ok.
What option I need to activate or deactivate in the connection in WinSCP 6.1.2?

Please help. I need the scripting feature from WinSCP.

The error message is "Failure reading network stream".