Are the DN's functioning properly ? Can you check if the datanodes are in exclude list ?
Suspected from below error from logs -
There are 3 datanode(s) running and 3 node(s) are excluded in this operation.
Can you make sure port are open?
Chcek if you are able to connect to 50010, try writing some sample data to remote cluster from existing node.
@hardik desai, you may turn on debug log in the namenode for
so that it will print more information in the namenode log on why the datanodes are excluded.