This error can happen in two cases:
- You hit our anti-spam limit, which prevents users from placing more than 256 orders within a 2-minute time frame.
- You hit our throttle dynamic limit, which prevents users from placing a new order when the trade engine lag increases. It is very rare, generally does not last more than a few seconds, and is designed to mitigate attacks by spam orders, regulate lag during a spike in activity, and avoid flash crashes.