If you changed the parameter "Password Access" to false it means that password authentication is then disabled.
If you then try to connect with a client that doesn't use a certificate to authenticate then you will get the "no authentication method" error.
If using putty to connect you need to setup putty to use the private key when connecting and also if you used a password to protect the certificates with (entered during creation) you need to enter the same password to putty, if not then putty will not be able to use the certificate.
Good luck.