Re: Server unexpectedly closed network connection
It's quite likely the server got upgraded and is not compatible anymore with the 6 years old version of WinSCP you are using. Please try to to upgrade.
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
. 2021-10-19 15:40:12.337 --------------------------------------------------------------------------
. 2021-10-19 15:40:12.337 WinSCP Version 5.5.4 (Build 4433) (OS 6.3.9600 - Windows Server 2012 R2 Datacenter)
. 2021-10-19 15:40:12.337 Configuration: C:\xxx\WinSCP.ini
. 2021-10-19 15:40:12.337 Local account: xxxx\xxxxxxx
. 2021-10-19 15:40:12.337 Working directory: C:\xxx
. 2021-10-19 15:40:12.337 Process ID: 1840
. 2021-10-19 15:40:12.337 Command-line: "C:\xxx\WinSCP.exe"
. 2021-10-19 15:40:12.337 Time zone: Current: GMT-5, Standard: GMT-6 (Central Standard Time), DST: GMT-5 (Central Daylight Time), DST Start: 3/14/2021, DST End: 11/7/2021
. 2021-10-19 15:40:12.337 Login time: Tuesday, October 19, 2021 3:40:12 PM
. 2021-10-19 15:40:12.337 --------------------------------------------------------------------------
. 2021-10-19 15:40:12.337 Session name: xxxxxxxxx@xxxxxx.com (Site)
. 2021-10-19 15:40:12.337 Host name: sftp.xxxxxxx.com (Port: 22)
. 2021-10-19 15:40:12.337 User name: xxxxxxxx (Password: Yes, Key file: No)
. 2021-10-19 15:40:12.337 Tunnel: No
. 2021-10-19 15:40:12.337 Transfer Protocol: SFTP (SCP)
. 2021-10-19 15:40:12.337 Ping type: -, Ping interval: 30 sec; Timeout: 15 sec
. 2021-10-19 15:40:12.337 Proxy: none
. 2021-10-19 15:40:12.337 Send buffer: 262144
. 2021-10-19 15:40:12.337 SSH protocol version: 2; Compression: No
. 2021-10-19 15:40:12.337 Bypass authentication: No
. 2021-10-19 15:40:12.337 Try agent: Yes; Agent forwarding: No; TIS/CryptoCard: No; KI: Yes; GSSAPI: Yes
. 2021-10-19 15:40:12.337 GSSAPI: Forwarding: No; Server realm:
. 2021-10-19 15:40:12.337 Ciphers: aes,blowfish,3des,WARN,arcfour,des; Ssh2DES: No
. 2021-10-19 15:40:12.337 SSH Bugs: A,A,A,A,A,A,A,A,A,A
. 2021-10-19 15:40:12.337 Simple channel: Yes
. 2021-10-19 15:40:12.337 Return code variable: Autodetect; Lookup user groups: A
. 2021-10-19 15:40:12.337 Shell: default
. 2021-10-19 15:40:12.337 EOL: 0, UTF: 2
. 2021-10-19 15:40:12.337 Clear aliases: Yes, Unset nat.vars: Yes, Resolve symlinks: Yes
. 2021-10-19 15:40:12.337 LS: ls -la, Ign LS warn: Yes, Scp1 Comp: No
. 2021-10-19 15:40:12.337 SFTP Bugs: A,A
. 2021-10-19 15:40:12.337 SFTP Server: default
. 2021-10-19 15:40:12.337 Local directory: C:\Users\xxxxxxxxxx\Documents, Remote directory: /, Update: Yes, Cache: Yes
. 2021-10-19 15:40:12.337 Cache directory changes: Yes, Permanent: Yes
. 2021-10-19 15:40:12.337 DST mode: 1; Timezone offset: 0h 0m
. 2021-10-19 15:40:12.337 --------------------------------------------------------------------------
. 2021-10-19 15:40:12.415 Looking up host "sftp.xxxxxxxxxx.com"
. 2021-10-19 15:40:12.415 Connecting to xx.xx.xxx.xx port 22
. 2021-10-19 15:40:12.508 Server version: SSH-2.0-WS_FTP-SSH_8.7.0.105
. 2021-10-19 15:40:12.508 Using SSH protocol version 2
. 2021-10-19 15:40:12.508 We claim version: SSH-2.0-WinSCP_release_5.5.4
. 2021-10-19 15:40:12.540 Doing Diffie-Hellman group exchange
. 2021-10-19 15:40:12.680 Server unexpectedly closed network connection
. 2021-10-19 15:40:12.680 Knocking FTP port.
. 2021-10-19 15:40:14.681 FTP port did not open.
* 2021-10-19 15:40:14.728 (EFatal) Server unexpectedly closed network connection.