Can connect to SFTP server from a command line but WinSCP fails....

Hi, I am absolutely beating my head against the wall on this one.

I can connect to a SFTP server (Linux) at my workplace from a Windows Server 2012 machine via PSFTP, sftp.exe and another staff showed a connection via scp from a command line.

But despite using the same private key, converted from Openssh via PuTTYgen, I cannot connect with WinSCP. It keeps saying server refused the key and then asks for a password. But I did not configure a passphrase for the key and the user account is not using password. Not really sure what I am doing wrong or where to begin troubleshooting.

If anyone has any thoughts, it would be greatly appreciated.

You most likely have an old version of WinSCP, which does not support SHA2:
Issue 1952 – Support rsa-sha2-256 and rsa-sha2-512 SSH public key algorithms
Make sure you upgrade to the latest version.