Could be anything. Most likely scenario is the internal error is a load shedding error and the 503s were when the system became completely unresponsive. If it w

Could be anything. Most likely scenario is the internal error is a load shedding error and the 503s were when the system became completely unresponsive. If it was a configuration issue then it is more likely that it would have directly recovered rather than going 'internal error -> 503 -> internal error'.