You can connect to either an embedded (in Data Studio) or a separate instance of the Find duplicates server. By default, Data Studio will connect to the embedded instance, which will run automatically together with the Data Studio service.
If the Find duplicates step was previously disabled or configured to connect to a separate instance, you have to restart Data Studio to reconnect to the embedded instance.
If you've made any changes to the Workflow or your data source after running the Find duplicates step, you may have to click Clear saved results to clear the cache containing the results. Note that this option will be disabled if there are no stored results or the cache has already been cleared.