As far as I know, the current release of the Governance Dashboard doesn't do NPrinting logs. Just QlikView service logs.
Neither are there any monitoring tools included in v17.3 or earlier of NPrinting. They tell me that Advanced Logging and Monitoring is to be included in a future release. No idea which one or when.
What certainly could be of help to get hold of failed jobs and the probable cause of the failure is the hidden Executions tab in the WebConsole.
How to reach it?
Open the NPrinting WebConsole and log in (preferably as admin, not tested whether this also works for other roles)
Click Tasks->Publish Task
In the browser address bar, there should now be an URL that ends with #/tasks/publish.
Replace the word publish with executions and press Enter.
You'll get an overview of all complete NPrinting task runs (successes and failures). For a failed task, click the blue GUID (the hexadecimal code at the front) and you'll get a detailed overview of all stages and error messages.