Working with Grpc in AWS ECS

Hi, I have deployed 2 applications in AWS ECS by using Grpc to communicate with each other. However, everytimes the client tried to connect to the server, it complains that the connection is refused. I am using DNS(Route 53) and NettyChannelBuilder to build the connection. I have exposed the client and server port when creating the task.

Another thing that I have tried is to create ALB in the server, I also got the same error (Connection refused. No further information). Tried deploying appMesh, it stucks at PRE_INITIALIZING state. May I know what should I do to fix the issue?

Note; There is no problem when I deployed the 2 applications in company VM.