I noticed that the data that was saved into a database that I created with the application connected to the local shell does not show in Mongo Atlas when the application is connected to the Atlas. But the data added after connected to the Atlas does show. Is this by design or there is something I am missing to get data saved on local mongo shell to show in the cluster?
Can you post a screenshot of how you did the above? I suspect that the application was connected to a local mongod rather than Atlas because the is no reason why the data is not in Atlas if you added it while being connected to Atlas.