A response code of 502 means one of our servers or other intermediary data service is temporarily offline. It should be a very rare event, requiring no action on your part.
A response code of 503 means that a service was unavailable, and may occur sometimes when our servers (or third-party services) are under heavy load. If you are encountering 503 errors, we recommend waiting a brief period, and retrying your requests with an exponential backoff in your request rate, as subsequent API requests would typically succeed.
A response code of 504 means a request is taking too long and has timed out before we were able to generate a response. While we work hard to minimize this kind of event, it may happen when requesting complex data or when our servers are under high load. Please contact us if you encounter this error repeatedly.