There's a new version of the HubSpot API
As of November 30, 2022, HubSpot API keys are no longer a supported authentication method for accessing HubSpot APIs. Instead, you should use a private app access token or OAuth to authenticate API calls. Learn more about this change and how to migrate an API key integration to use a private app instead.
Your app ID can be found below the name of your app when viewing the Apps dashboard in your developer account.
The app ID is also displayed when viewing the auth settings for your app.