Twilio will return this error code if a resource is currently unavailable. Please wait a few moments and then try the request again. We apologize for the inconvenience.
If you are seeing a consistent pattern of 503 server errors coming from the Twilio API, check our status page for more details. If our status page has no information, contact support with details about the requests that are failing, and we will investigate.
This error code indicates the request is safe to retry at a later time.