How do I manually clear a 'Printer Offline' error that's causing the HP printer to be in error mode?

Check the printer's power cable and USB connection (if applicable). Ensure the printer is properly connected to the network (if using Wi-Fi). Restart both the printer and your computer. In Windows, check the Devices and Printers list to see if the printer is listed and accessible. If not, try removing and re-adding the printer.