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:

How to Connect to your Server via FTP with Notepad++

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