Unable to Add Node to Replica Set Cluster

Yes, Mongod is running on all nodes and can ping and connect to them all.
I have not initialized third node because it is currently using by developers for testing so as soon as the replication succeds i will add the third node to the cluster. I have stopped firewall in all nodes so i think it is not firewall issue.
the log file shows:

{"t":{"$date":"2022-11-09T23:35:50.237+08:00"},"s":"I",  "c":"CONNPOOL", "id":22576,   "ctx":"ReplNetwork","msg":"Connecting","attr":{"hostAndPort":"SECONDNODE:27017"}}