Post a reply

Before posting, please read how to report bug or request support effectively.

Bug reports without an attached log file are usually useless.

Options
Add an Attachment

If you do not want to add an Attachment to your Post, please leave the Fields blank.

(maximum 10 MB; please compress large files; only common media, archive, text and programming file formats are allowed)

Options

Topic review

Watson@hashtagresilience.com

upload error to BOX

I am using the latest version and a recent upgrade is not the issue

Edition Windows 11 Pro
Version 25H2
Installed on ‎10/‎3/‎2025
OS build 26200.6899
Experience Windows Feature Experience Pack 1000.26100.253.0
64 bit

Transfer protocol SFTP
using commander interface

ERROR MESSAGE
Received unexpected packet in response to authentication request, type 6245416 (unknown)
Error
Authentication log (see session log for details):
Using username "technology@americanbackcountry.com".

Authentication failed.
see attached zip file for log

I am trying to SFTP a very large file storage to Box.com
The initial login is fine - but during the upload I get the above error

Here is a loom that shows my initial logging on - which is fine
https://www.loom.com/share/6f402d26f0464ac3aedc8997f821aa2a

Thanks for your help with this -
The objective is to migrate a several terabytes of data to BOX.com in a few weeks
links to resources that detail how to configure for speed greatly appreciated
Thanks
Watson




Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.). If you are not able to reproduce the problem with the steps, it is probably not worth to report it as I will not be able to reproduce it (and solve) too.
Particularly, if the problem relates to user interface, consider recording your steps or even full video. E.g. using Start recording function of Game bar in Windows 11 and Windows 102 or Steps Recorder in Windows 7 or newer3 or similar service.
If your problems relates to interaction with remote server, please post a full log file showing the problem.
To generate log file, enable session logging, log in to your server and do the operation and only the operation that causes the error.
Always attach your log to the post as a file, never paste the log into post text. When posting extensive logs please compress them before attaching.
Note that passwords and passphrases are not stored in the log. You may want to remove other data you consider sensitive though, such as host names, IP addresses, account names or file names (unless they are relevant to the problem).
If you do not want to post the log publicly, you can mark the attachment as private.
For scripting/automation-related issues, include your full script, command-line you use to run WinSCP, and output you s