The solution for me was to use puttygen to export a .ppk version of my private key to OpenSSH as follows: Open PuttyGen Menu: Conversion -> Export OpenSSH key Save your new key (don’t forget to make it clear it is openssh)This was weird seeing as my .ppk was converted from a private key generated by OpenSSH itself.I think it has to do with the fact that my original key starts with—- BEGIN SSH2 ENCRYPTED PRIVATE KEY —-whereas the exported key starts with—–BEGIN RSA PRIVATE KEY—–