# Starting the Subscriber and Publisher Clients

Start the subscribers, as described in Starting the Subscriber Clients. Note that you cannot start `user1` as a subscriber because `user1` has permission to publish, but not to subscribe. As a result, you receive an exception message including the statement:

       Operation not permitted.

`User2` should start as a subscriber in the same manner as before.

You can now start `user1` as the publisher and send messages to `user2`, as described in Starting the Publisher Client and Sending Messages.

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