If the problem is probably related to the port configuration.
If your Dell printer is on a network, which has an IP address the most likely cause for the offline status is that the
printer's IP address has changed, but the port configuration still refers to the old IP address.
Print a network configuration page to first obtain the printer's IP address.
On the printer's menu navigate to system setup and then to reports.
Now select configuration and press OK.
Press OK again to print the configuration page.
Once you have the IP address go to Control Panel and then to Devices and Printers.
Right-click on the printer and select printers properties.
In the printer properties window select the port tab.
This will show you the selected printer's port, now press the configure port.
The next window will show you the printer's IP address which the windows think it has.
If the IP address differs from the one you obtain through the network configuration page update the IP address.
If you see an error message you have to add a new TCP/IP port.
Once again open the printer properties windows as mentioned above.
Press the port tab and then click on add port.
In the next window choose the Standard TCP/IP port option and click on the new port.
Once in the Standard TCP/IP port wizard, click on Next.
Outdated or faulty printer drivers can hinder the communication between the printer and the computer.
This may cause the Dell printer offline issue. Completely uninstalling and then reinstalling the latest
drivers for your Dell printer is likely to sort out the error.
To uninstall the printer's driver go to the start menu and open the run window.
Now type printui /s /t2 and press enter.
The Print Server Properties window will open up, click on the drivers' tab.
Select your Dell printer drivers and click on remove.
If prompted for, choose the option Remove drivers and driver package and then click on delete.
Now download the latest drivers for your Dell printer and install them.
Open the Dell webpage and go to the Dell Drivers page.
You have to enter the printer's service tag.
In case you don't have the tag, you can click on the view products tab and then select your printer's
model.
Every printer has its model number printed on it, so you can easily find the model number of your Dell
printer.
Now select the operating system installed on your computer.
After this, you will find the list of all the available software utilities and drivers for your printer's model.