NodeJS ssh2 Cannot parse privateKey

Question

I am getting this error while trying to open a tunnel with ssh2 in a nodeJS app.

Error: Cannot parse privateKey: Unsupported key format

I followed the steps from this thread and I've converted my existing key from openSSH to the RSA format and confirmed in the key headers that has indeed been converted. However, when I try opening my connection I still get the error.

This is my code

function SSHConnection() {
  return new Promise((resolve, reject) => {
    sshClient.on('ready', () => {
      sshClient.forwardOut(
        forwardConfig.srcHost,
        forwardConfig.srcPort,
        forwardConfig.dstHost,
        forwardConfig.dstPort,
        (err, stream) => {
          if (err) reject(err);

          // create a new DB server object including stream
          const updatedDbServer = {
            ...dbServer,
            stream
          };
          // connect to mysql
          const connection =  mysql.createConnection(updatedDbServer);
          // check for successful connection
          //  resolve or reject the Promise accordingly
          connection.connect((error) => {
            if (error) {
              reject(error);
            }
            resolve(connection);
          });
        });
    }).connect(tunnelConfig);
  });
}