After a server reboot none of the users in the office can log into it using WinSCP anymore. All users are using password protected .ppk keys. They can still log in fine via putty (w. pageant) and I can log in fine using shell (ie. not a server problem) - just not using WinSCP.
Below is an extract of the servers authlog:
Jun 14 14:38:54 r2d2 sshd: Accepted publickey for username from 18.104.22.168 port 3127 ssh2
Jun 14 14:38:55 r2d2 sshd: (pam_unix) session opened for user username by (uid=0)
Jun 14 14:38:55 r2d2 sshd: subsystem request for sftp
Jun 14 14:38:55 r2d2 sshd: (pam_unix) session closed for user username
Here is the WinSCP logs: