subscriber does not listen to my gmail emails

Question

I'm struggling with the pub/sub api. I have followed this guide. I have created my project, my topic, set up with [email protected] to be the publisher, and my subscription.

And finally, that's my code

import os
from google.cloud import pubsub_v1
from concurrent.futures import TimeoutError

credentials_path = os.getcwd() + '/credentials.json'
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = credentials_path


timeout = 5.0

subscriber = pubsub_v1.SubscriberClient()
subscription_path = 'MY_SUBSCRIPTION_PATH'


def callback(message):
    print(f'Received message: {message}')
    print(f'data: {message.data}')

    if message.attributes:
        print("Attributes:")
        for key in message.attributes:
            value = message.attributes.get(key)
            print(f"{key}: {value}")

    message.ack()           


streaming_pull_future = subscriber.subscribe(subscription_path, callback=callback)
print(f'Listening for messages on {subscription_path}')


with subscriber:
    try:
        streaming_pull_future.result()
    except (TimeoutError, KeyboardInterrupt):
        streaming_pull_future.cancel()
        streaming_pull_future.result()

Because the GH code of gmail's pub/sub didn't work, I got this one from a guide, thus I had to create a service account. Everything seems to work fine, in fact, if I publish a message on the pub/sub api the subscriber is able to catch it.

But if I send a message to myself to my gmail, it's not able to see it.