5.1.3 Unable to connect to proxy with k8s loadbalancer service

[seeyou112d]

Hi ,
I am setting up RocketMQ cluster with k8s (alibaba cloud ack) and created service for proxy for client to connect. It is working fine when I use Nodeport type service with public IP address enable and the client can connect to the MQ and send/receive message successfully.
However, I would like to enhance the availability by using a load balancer type service, so as not to be affected by node failure. I am able to telnet to the SLB ip + port, but client cannot connect , it just wait until timeout and throw task cancel error.
I have also tried to create a SLB target group with the Node port as listener, but it is not working as well.
Can help suggest what I should check please?
thanks.