No Data move on New node?

Server Architecture : 1 master(m1) and 3 data node (n1,n2,n3) 20 shard
Issue : data replicated on two node n1, n2 but not any data on n3
I don't know why data not moved to my new node n3.
Is there any issue or it is a normal process.

Does that node have anything on it?

Do you have at least 85% free space on the data partition of node n3? That's the default threshold for shard allocations.

You could use the cluster reroute API with explain=1 to have ES report why it's not able to reroute the shard to a particular node.