The issue might arise due to your printer, computer, or wireless network if the 'Epson wf-3640 offline' error is displayed. At that time, perform the following techniques. Run a nozzle test from the device's control panel to see whether the printer can print without the need for a PC. If you are unable to print a nozzle check pattern, examine the LCD display of the product for trouble warnings. Clear any mistakes indicated on the LCD before attempting to print another nozzle test pattern.