cannot receive notification from Firebase Cloud Messaging

Question

i want to send push notification to my device with Firebase Cloud Messaging, everything is fine while using Firebase Composer panel, i can send and receive Messages through composer, but when i want to do it with python, i don't receive any Message on my device though The response says that Message sent successfully , here is my code:

from __future__ import print_function

import datetime
import firebase_admin
from firebase_admin import messaging
from firebase_admin import credentials
        

def send_to_token():
    # [START send_to_token]
    # This registration token comes from the client FCM SDKs.
    registration_token = 'my-android-device-registration-token'

    # See documentation on defining a message payload.
    message = messaging.Message(
        data={
            'score': '850',
            'time': '2:45',
        },
        token=registration_token
    )

    # Send a message to the device corresponding to the provided
    # registration token.
    response = messaging.send( message)
    # Response is a message ID string.
    print('Successfully sent message:', response)
    # [END send_to_token]

if not firebase_admin._apps:
    cred = credentials.Certificate('google.json') 
    default_app = firebase_admin.initialize_app(cred)

send_to_token()

and it gives me this response that indicates successful operation:

projects/app-name/messages/0:1650xxxxx4999573%4bf3b6xxxxxd7ecd

but i don't receive any notification on my device and i cant find the problem.

so where is my problem? is it in my code?

thank you.