title: AWS DMS "Load complete, replication ongoing" not working MongoDB to DocDB
body: <p>I am trying to make a PoC for MongoDB to DocDB migration with DMS.
  I've set up a MongoDB instance with some dummy data and an empty DocDB. Source and Target endpoints are also set in DMS and both of them are connecting successfully to my databases.</p>
  
  <p>When I create a migration task in DMS everything seems to be working fine. All existing data is successfully replicated from the MongoDB instance to DocDB and the migration task state is at "<strong>Load complete, replication ongoing</strong>".
  At this point I tried creating new entries in existing collections as well as creating new empty collections in MongoDB but nothing happens in DocDB. If I understand correctly the replication should be real time and anything I create should be replicated instantly?
  Also there are no indication of errors or warnings whatsoever... I don't suppose its a connectivity issue to the databases since the initial data is being replicated.
  Also the users I am using for the migration have admin privileges in both databases.</p>
  
  <p>Does anyone have any suggestions?</p>