Hi @lu1986.
It's actually an expected behavior for the RTDM. Since on the channel level (HTTP) request/response went through successfully the response code will be 200 no matter what the error appeared in the RTDM log.
Am I assuming you're tiring to configure health check on load balancer?
If it's the case I would recommend configuring health check not based on the return code, but rather on the return value.
You can configure it to consider node healthy if the reply contains word "success", or any other words for the successful reply, otherwise to consider it unhealthy.
Ivan Baranov, Tier One Analytics