NestJs GraphQL playground access

I can't seem to access the GraphQL Playground using NestJS. I'm exploring the documentation and have followed this https://docs.nestjs.com/graphql/quick-start up to the Resolvers section to generate the schema.gql, but attempting to reach localhost:3000/graphql is not able to connect.

At first I thought my code was setup incorrectly, but I spent some time digging into Nest's examples and found that those also do not work when trying to access the /graphql endpoint. It does work if I setup a get endpoint to return a JSON body using the REST method.

import { Module } from '@nestjs/common';
import { GraphQLModule } from '@nestjs/graphql';
import { RecipesModule } from './recipes/recipes.module';

@Module({
  imports: [
    RecipesModule,
    GraphQLModule.forRoot({
      installSubscriptionHandlers: true,
      autoSchemaFile: 'schema.gql',
    }),
  ],
})
export class AppModule {}

This is directly from the NestJS example. My understanding is that the GraphQLModule should be setting up the connection to the /graphql endpoint. Following the docs, graphql, apollo-server-express, and graphql-tools were all installed.

Any idea why the graphql route is not connecting?

[Edit]: Things I've tried so far:

• setting playground: true explicitly with GraphQLModule.forRoot
• verified NODE_ENV is not 'production'
• confirmed server works when creating resolvers using REST
• curl'd localhost:3000/graphql and receive a graphql validation error, so confirm that connects correctly

sometimes helmet causes this same issue. if you have helmet loaded as a middleware, it might probably also cause this.