Binance SpotWebsocketClient not sending responses for a subscribed symbol

Question

I am running the following code on a Jupyter Notebook with testing purposes:

import json
import datetime
from binance.websocket.spot.websocket_client import SpotWebsocketClient

def safe_json_load(message):
    try:
        return json.loads(message)
    except:
        return {}

def message_handler(message):
    if not isinstance(message, dict):
        message = safe_json_loads(message)
    if isinstance(message, dict) and 'E' in message and 's' in message and 'c' in message:
        timestamp = datetime.datetime.utcfromtimestamp(int(message['E'])/1000)
        last_price = float(message['c'])
        output = {
            'timestamp': timestamp,
            'symbol': message['s'],
            'price': last_price
        }
        print(output)
    else:
        print(message)

wss_client = SpotWebsocketClient(stream_url="wss://stream.binance.com:9443")
wss_client.start()

# Live subscription
wss_client.ticker(
    symbol='hbarusdt@ticker',
    id=1,
    callback=message_handler
)

When building the message handler I was able to retrieve the symbol information. However at certain time it stopped to print the data. I have checked that if set the ticker symbol to hbarusdt instead of hbarusdt@ticker it prints data again but, why was it working before and not now?

Also, I would like to now how can I remove the live subscription in a similar way as I am creating it? In the future I want to deploy the solution to the cloud as a data scraper, so I may need to first try to remove previously existing subscriptions with the same ID in case the script fails and I need to start it again.