What are the most common causes of a 403 error when using the Interactive Brokers API?

Common causes include: incorrect API permissions configured in your IB account (e.g., not having 'trading' permission for an account), using an outdated or invalid API key/password, attempting to access data or functionality you're not authorized for (e.g., placing orders on a read-only account), IP address restrictions in your IB account, or exceeding API rate limits.