If your printer displays an offline notice, it's because it's having trouble communicating with your Mac. There are a variety of reasons why is my printer offline Mac, ranging from connectivity issues to a printer malfunction. Whatever the cause, there are a few things you can do to figure out what the problem is. Click "System Preferences" and then "Print & Scan." to bring it back online. If yellow light displays next to the printer's name, double-click it from the Printer list. Then select "Resume" from the drop-down menu.