LN error

test.js

'use strict';

const grpc = require('grpc');
const fs = require("fs");

//  Lnd cert is at ~/.lnd/tls.cert on Linux and
//  ~/Library/Application Support/Lnd/tls.cert on Mac
const lndCert = fs.readFileSync('/Users/mcgingras/Library/Application Support/LND/tls.cert');
const adminMacaroon = fs.readFileSync('/Users/mcgingras/Library/Application Support/LND/admin.macaroon');
const meta = new grpc.Metadata();
meta.add('macaroon', adminMacaroon.toString('hex'));

// We order the suites by priority, based on the recommendations provided by SSL Labs here:
// https://github.com/ssllabs/research/wiki/SSL-and-TLS-Deployment-Best-Practices#23-use-secure-cipher-suites
process.env.GRPC_SSL_CIPHER_SUITES = process.env.GRPC_SSL_CIPHER_SUITES || [
  'ECDHE-ECDSA-AES128-GCM-SHA256',
  'ECDHE-ECDSA-AES256-GCM-SHA384',
  'ECDHE-ECDSA-AES128-CBC-SHA256',
  'ECDHE-ECDSA-CHACHA20-POLY1305'
].join(':')

const credentials = grpc.credentials.createSsl(lndCert);
const rpc = grpc.load("./config/rpc.proto");

const lightning = new rpc.lnrpc.Lightning('localhost:10001', credentials);
const walletUnlocker = new rpc.lnrpc.WalletUnlocker('localhost:10001', credentials);


// this one works fine
var _call = lightning.walletBalance({}, meta, function(err, response) {
    if (err) console.log(err);
    if (response) console.log(response);
});

// this one returns an error
var _call = walletUnlocker.initWallet({}, meta, function(err, response) {
    if (err) console.log(err);
    if (response) console.log(response);
});