@DragonX256: Thanks for your feedback.

Yes, this dev version works! Thank you!

@DragonX256: Thanks.

This issue is being tracked here:
Issue 1952 – Support rsa-sha2-256 and rsa-sha2-512 SSH public key algorithms

Workaround is mentioned in the tracker.

I'm sending you an email with a development version of WinSCP to the address you have used to register on this forum.

@martin: Okay.

password: winscptest

@DragonX256: Thanks. May I get a test account on your server?

Can confirm this issue too – I can connect with PuTTY or ssh from Git for Windows, but cannot in WinSCP.
Here's my logs
PuTTY: https://pastebin.com/ic5JLMZ3
WinSCP: https://pastebin.com/HmFQKwuL

Please attach WinSCP session log file and PuTTY event log.

Hey, I have updated my ArchLinux deciated server today (Pacman -Syu), it update OpenSSH to version 8.8p1-1, after that, I cannot longer connect to my dedicated server. Message is:

WinSCP error:

Authentication log (see session log for details):
Using username "root".
Server refused our key.

Authentication failed.

Server side error:

userauth_pubkey: key type ssh-rsa not in PubkeyAcceptedAlgorithms [preauth]

However, if I right click on my dedicated server in site list of WinSCP and I click on Open in PuTTY, PuTTY works fine. So I am thinking of a problem with WinSCP since the last version of OpenSSH (8.8p1-1).

I don't have any problem on my other dedicated server with ArchLinux also, but not updated (OpenSSH 8.5p1-1).

It's seems to be a problem with SSH-RSA key type which has been deprecated, idk, see the OpenSSH changelog: https://www.openssh.com/releasenotes.html

Using WinSCP v5.19.2 (B 11614)