serverless: Unable to deploy to Serverless due to 'empty zip'

I have a GraphQL API that has two indexes, one runs Express (index.js) and the other runs Serverless (indexServerless.js). For the Serverless I use serverless-offline to test the API out of Serverless. I tested both Express and Serverless locally and both of them are working. If I try to deploy to Serverless through serverless login and serverless deploy I receive the following message from Serverless CLI:

An error occurred: GraphqlLambdaFunction - Uploaded file must be a non-empty zip (Service: AWSLambdaInternal; Status Code: 400; Error Code: InvalidParameterValueException

And this one from Cloudformation:

UPDATE_COMPLETE
UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS
UPDATE_ROLLBACK_COMPLETE

Which is strange cause I have not changed the API since the last deploy so I contacted Serverless support but they throw GraphQL into the conversation and told me that they could not help me, any idea on how to fix it?

Here’s the serverless.yml:

org: X

app: X

service: X

provider:
  name: aws
  runtime: nodejs12.x
  stage: production # development
  region: eu-central-1

plugins:
  - serverless-offline

functions:
  graphql:
    handler: indexServerless.graphqlServerless
    timeout: 20
    events:
      - http:
          path: graphql
          method: post
          cors: true

The indexServerless.js:

const { graphqlServerless } = require("./graphql");

require("dotenv").config();

module.exports.graphqlServerless = graphqlServerless;

And the graphql.js, which export both configurations, i.e Express and Serverless:

// Apollo serverless
const graphqlServerless = new ApolloServerless({
  typeDefs,
  resolvers,
  cors: false,
  playground: {
    endpoint: "/dev/graphql",
  },
  introspection: false,
  debug: false,
  mocks: false,
  schemaDirectives: {
    auth: directives.AuthDirective,
    guest: directives.GuestDirective,
  },
  context: ({ event, context }) => {
    return {
      headers: event.headers,
      functionName: context.functionName,
      event,
      context,
    };
  },
});

module.exports = {
  graphqlServer, // Express
  graphqlServerless: graphqlServerless.createHandler({
    cors: {
      origin: process.env.GRAPHQL_CORS_SERVERLESS, // true
      credentials: true,
    },
  }), // Serverless
};

I tried to exclude node_modules by setting exclude on serverless.yml and update the Node version, but no changes.

Here’s the Serverless CLI version:

Framework Core: 2.19.0
Plugin: 4.4.2
SDK: 2.3.2
Components: 3.4.7

And the Node dependencies:

{
    "apollo-server-express": "^2.19.2",
    "apollo-server-lambda": "^2.19.2"
}