It's the same issue as this: Request failed: Failed to receive message header
The cause is that it takes too long to process before transmitting the next progress message, so the request system presumes the request is stuck and allows the user to make more requests. But the simulation continues to run on the server after the Request failed: Timeout waiting for message error, so it is not safe to retry.
As mentioned on the other thread, you can work around it by removing the 3 unused AIFactor() nodes from your ranking system.