How to make Coinbase API keys work?

[twoletters]

I use the current CryptoStore container to collect data from exchanges. A proper config file is passed to it through the CONFIG environment variable to provide it with the Coinbase API keys it needs. However, I still get the following error message:

coinbase-1  | 2024-06-25 21:10:16,522 : WARNING : COINBASE: Invalid message type {'type': 'error', 'message': 'Failed to subscribe', 'reason': 'level2, level3, and full channels now require authentication. https://docs.cloud.coinbase.com/exchange/docs/websocket-auth'}

My config file contains the following excerpt:

coinbase:
  key_id: xxxx
  key_secret: xxxx
  key_passphrase: null

As you can see, I don't have a passphrase for this key. I use a regular Coinbase account, which does not let me set a passphrase when creating a new API key, be it a legacy key or a key created through the Coinbase developer platform. Am I looking at the wrong place for this, or has Coinbase shuffled things around once again? I would greatly appreciate a quick tutorial or pointer here, from anyone who made it work.