I am trying to use Coinbase in Sandbox mode to try out a strategy.

I created an Sandbox API using the instructions here https://docs.cdp.coinbase.com/exchange/docs/sandbox/

However, when I use them in a Python script, they don’t work. It returns an error.

I am using a simple script

from coinbase.wallet.client import Client
import os
from dotenv import load_dotenv

# Load environment variables from a .env file
load_dotenv()

# Your API credentials from Coinbase
API_KEY = os.getenv("API_KEY")
API_SECRET = os.getenv("API_SECRET")

# Initialize the Coinbase client
client = Client(API_KEY, API_SECRET)

def get_cash_balance():
    # Get accounts
    accounts = client.get_accounts()

    # Find and print the cash balances
    for account in accounts.data:
        if account['type'] == 'fiat':
            print(f"Currency: {account['currency']}")
            print(f"Balance: {account['balance']['amount']}{account['balance']['currency']}")

if __name__ == "__main__":
    get_cash_balance()

It gives me an error ending with

raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Am I doing something wrong? How can I fix this? My keys are exactly as they were on the site.

I even tried using curl

curl -X GET https://api.coinbase.com/v2/accounts -u "API_KEY:API_SECRET"

The response from that is Unauthorized