None of the server’s authentication methods were accepted. Please check the options under the authentication tab.

If trying to connect with Notepad++ to an OS X El Capitain ssh default server, you get the error:

you could edit your connection’s settings to use keyboard interactive authentication, instead of password authentication:

Profile settings > Select the desired connection > Authentication > Check “Try keyboard interactive authentication”

More info here:

http://www.inmotionhosting.com/support/website/ftp-client-setup/connect-ftp-notepad-plus

The starting point for another aproach can be found withing the following two links:

http://serverfault.com/questions/85992/how-do-i-setup-sshd-on-mac-os-x-to-only-allow-key-based-authentication

http://superuser.com/questions/364304/how-do-i-configure-ssh-on-os-x