Hi stennie,
The thing is, I have just captured an image “actually AMI because I am using AWS” and the machine which I captured image from, it was working properly with no issues and no local DNS reolution as you have suggested.
In the old machine i had not used replicaset members as they should be used, I just enabled replicaset in the .cfg file and added a name for it, so later I can add members when I decide to do that.
so, for new machine, I just spined up another mongoDB machine from the image and applied the machine NEW elastic ip in the application code which already in another machine.
All things should work properly as before but unfortunately no.