If PaperCut shows a pop-up error after boot, "Unable to connect to server":
In this case, the PaperCut app (PCClient) has launched before Wi-Fi has a chance to connect to the internet.
This error message is benign and it is okay to hit “OK”. The next step is for the user to launch the "PCClient" app from the Applications folder or Launchpad when they need to print.