SFTP with SSH key - No supported authentication methods available?

Hi, I'm trying to use Directory Opus to connect to a SFTP site with a private key file.

I have entered my credentials into address book and verified they are correct, I have pointed Opus to the PPK key file, but Opus will not connect, it says:-

"SSH: Fatal: Disconnected: No supported authentication methods available (server sent: publickey)"

With the same credentials I am able to connect using FileZilla no problem, so why won't Opus connect?

If you search the forum for the error message, there are several other threads about it which may help.

Changing PPK file version to type 2 as per this thread solved it eventually - SFTP keys - #22 by Leo