Host based Connect - error java.io.IOException after requesting password for the key

[VladimZaguzin]

trying to use j2ssh to make a SSH2 Host based Connect

and getting error

com.sshtools.ssh.SshException: java.io.IOException at com.sshtools.ssh2.Ssh2HostbasedAuthentication.authenticate(Ssh2HostbasedAuthentication.java:112) at com.sshtools.ssh2.AuthenticationProtocol.authenticate(AuthenticationProtocol.java:206) at com.sshtools.ssh2.Ssh2Client.authenticate(Ssh2Client.java:340) at shh_test.main(shh_test.java:110)

Caused by: java.io.IOException: Failed to sign data! Could not sign data at com.sshtools.ssh.components.jce.Ssh2RsaPrivateCrtKey.sign(Ssh2RsaPrivateCrtKey.java:134) at com.sshtools.ssh2.Ssh2HostbasedAuthentication.authenticate(Ssh2HostbasedAuthentication.java:99)

i basically copied the example code from SSH2HostbasedConnect.java with small modifications such as hard-coded user name and host name

error happened at step

            SshKeyPair pair;
            if (pkfile.isPassphraseProtected()) {
                System.out.print("Passphrase: ");
                pair = pkfile.toKeyPair(reader.readLine());
            } else
                pair = pkfile.toKeyPair(null);

            pk.setPrivateKey(pair.getPrivateKey());
            pk.setPublicKey(pair.getPublicKey());
        } while (ssh.authenticate(pk) != SshAuthentication.COMPLETE
                && ssh.isConnected());

I know for sure that my private key is working and I used it in tactia; and it had status - opened

what can cause it ?