Redis sentinel not connect to master: Error: READONLY You can't write against a read only slave?

I have this redis replication with sentinel architect:

5 servers: .1, .2, .3, .4 and .5

• .1: nodejs app, redis master, redis sentinel
• .2: nodejs app, redis slave
• .3: nodejs app, redis slave
• .4: redis sentinel
• .5: redis sentinel

Sentinel handle failover as expected. redis-cli -h x.y.z.5 -p 26379 sentinel get-master-addr-by-name mymaster is always return .1 server.

My code to connect to this replication (I use ioredis):

let sentinels = [
  { host: process.env.REDIS_SENTINEL_1, port: process.env.REDIS_PORT },
  { host: process.env.REDIS_SENTINEL_2, port: process.env.REDIS_PORT },
  { host: process.env.REDIS_SENTINEL_3, port: process.env.REDIS_PORT }
]
store = new Redis({
  name: 'mymaster',
  sentinels: sentinels
})
store.on('ready', () => {
  store.set('foo', new Date())
  store.get('foo', function (err, result) {
    console.log('redis: get foo: ', result)
  });
});

Then, .1 nodejs app run ok, but in .2 and .3, the error occurs with this log:

 events.js:161
       throw er; // Unhandled 'error' event
       ^

 Error: READONLY You can't write against a read only slave.

P/s: my redis servers are binding in both server IP and 127.0.0.1. Because, without 127.0.0.1, I meet this error:

Error: Redis connection to 127.0.0.1:6379 failed - connect ECONNREFUSED 127.0.0.1:6379

So, I guess that, my app isn't connect to redis server via sentinel, but it connect directly with localhost.

Any help are appriciate!

via Justin