I'm having a terrible time getting SessionOptions.GiveUpSecurityAndAcceptAnyTlsHostCertificate to work on the GUI interface. I've tried all sorts of combinations, but whenever I click save, the values I enter disappear / don't work.
Can someone please provide a screenshot or show exactly what I need to enter to force WinSCP to ignore certificate problems (expired) for an FTP TLS connection?
So then it's not about the certificate.
It's about the TLS encryption.
Are you sure you are supposed to use the "Implicit TLS/SSL"? On port 21, "Explicit TLS/SSL" is typically used.
If you still have problems, please post new WinSCP log file and equivalent FileZilla verbose log file (not the GUI message log).