The outdated printer firmware may have caused the Dell Printer offline error on your Windows 10 device. You can follow the steps below to update the Dell printer firmware and fix the offline error:
• Step 1: Go to the ‘Drivers and Download’ page and download the firmware.
• Step 2: Run the Firmware Update Utility tool and choose the firmware
• Step 3: Select your specific Dell printer mode and click the ‘Update’ option to begin updating the printer firmware.
If you find that the offline error continues even after you update the printer firmware you can call the dell tech support number and ask for additional technical assistance so that you can implement more advanced troubleshooting steps.

Read More:- Dell Phone number