If you see this type of error you can:
Turn off your Printer
Simply disconnect your printer from your computer
If your printer is wired
Check your wire connection
Check USB cable that is proper connected or not
Connect your cable properly
Turn on your printer
And print your document
If your printer is wireless
Check your WIFI connection
Check your router
Turn on your printer
Check properly your connected network is must be right
Enter properly your ID and password
At last print your work
If you face any other problem related for HP Printer Offline with your printer, we are always available to assist you.