IPFS Private Network local peers discovery issue

I was able to make a private network by running my bootstrap node on the AWS server. However, if I connect to AWS bootstrap with several local nodes. Bootstrap can discover all my local nodes. But my some local nodes cannot find each other. And even some of the local nodes only discovering bootstrap and non-local nodes.

I followed GitHub repo guides for a private network.
Did I miss some configs to set?

P.S My aim to make my own network. As IPFS public network.