Issue with Error: All configured authentication methods failed

Hi there,

I'm trying to use your library to connect to a server via ssh but having some trouble. I'm stumbling on the Error: All configured authentication methods failed error message. However, when I try to connect with using ssh2 library by itself, it has no issue.

This example is how I connect using ssh2 library...

const connectionOptions = {
            host: hostname,
            port: port,
            username: username,
            privateKey: require('fs').readFileSync(path.resolve(__dirname, privateKeyLocation))
        };

        var conn = new Client();
        conn.on('ready', function () {
            conn.shell(function (err, stream) {
                if (err) {
                    return err;
                } else {
                    stream.on('close', function () {
                        console.log('Stream :: close');
                        conn.end();
                    }).on('data', function (data) {
                        console.log('OUTPUT: ' + data);
                    });
                    stream.end(commands);
                }

            });

        }).connect(connectionOptions);

This example is how I'm trying to use node-ssh. I also had an issue with the privateKey not being a string but it connects fine in first example without toString() method.

const connectionOptions = {
            host: hostname,
            port: port,
            username: username,
            privateKey: require('fs').readFileSync(path.resolve(__dirname, privateKeyLocation)).toString()
        };

        await ssh.connect(connectionOptions)
        const defaultDirectory = await ssh.exec('pwd', [], {
            stream: 'stdout'
        })
        const shellStream = await ssh.requestShell()

        const stdin = process.openStdin();
        stdin.addListener('data', (data) => {
            console.log('current path is', defaultDirectory)
            // Trim input to prevent the endings of lines in Windows ('\r\n\')
            shellStream.write(data.toString().trim() + '\n')
        })
        shellStream.on('data', (data) => {
            process.stdout.write(data)
        })
        shellStream.stderr.on('data', (data) => {
            process.stdout.write(data)
        })

I'm aware this error is common in Linux, but seems to only happen after I use this library. Could you point me in the right direction?

No source file or test is identified. Compare the two connection examples, focusing on the authentication options passed to node-ssh versus ssh2; done would require a reproducible diagnosis or documented fix for the authentication failure.