Error de configuración de connect-redis y express-session: UnhandledPromiseRejectionWarning: Error: El cliente está cerrado.

import { MikroORM } from '@mikro-orm/core';
import { ApolloServer } from 'apollo-server-express';
import express from 'express';
import { buildSchema } from 'type-graphql';
import { __prod__ } from './constants';
import mikroOrmConfig from './mikro-orm.config';
import { HelloResolver } from './resolvers/hello';
import { PostResolver } from './resolvers/post';
import { UserResolver } from './resolvers/user';

const main = async () => {
  const orm = await MikroORM.init(mikroOrmConfig);
  await orm.getMigrator().up();

  const app = express();

  const redis = require('redis');
  const connectRedis = require('connect-redis');
  const session = require('express-session');
  const RedisStore = connectRedis(session);

  const redisClient = redis.createClient({
    port: 6379,
    host: 'localhost',
  });

  app.use(
    session({
      name: 'qid',
      saveUninitialized: false,
      secret: 'sdfdsf24342fdsdfdsf23f2fdwf',
      resave: false,
      store: new RedisStore({
        client: redisClient,
        disableTouch: true,
      }),
      cookie: {
        maxAge: 86400 * 10, // 10 days
        httpOnly: true,
        secure: __prod__,
        sameSite: 'lax',
      },
    })
  );

  const apolloServer = new ApolloServer({
    schema: await buildSchema({
      resolvers: [HelloResolver, PostResolver, UserResolver],
      validate: false,
    }),

    // context is an object accessible by all the resolvers
    context: ({ req, res }) => ({ em: orm.em, req, res }),
  });

  apolloServer.applyMiddleware({ app });

  app.listen(4000, () => {
    console.log('El servidor se ha iniciado en el puerto 4000');
  });
};

main().catch(err => {
  console.error(err);
});

$ yarn dev
Resultado: El servidor se ha iniciado en el puerto 4000
Y después de 2 segundos:
UnhandledPromiseRejectionWarning: Error: El cliente está cerrado
    en Comandante. RedisClientsendCommand (/home/hleb/Projects/wreddit-server/node_modules/@node-redis/client/dist/lib/client/index.js:387:31)

¿Qué estoy haciendo mal?
Gracias.