What version of windows / mac are you using?|
Are you connecting through network?
One thing you do to get rid of the offline message in windows if it is a network printer.
Go to the devices and printers folder, right click on the printer and choose printer properties.
The click on the ports tab, click on the port with a checkbox and choose configure port. At the bottom, uncheck the box for SNMP status enabled. SNMP is what keeps telling your computer the printer is offline.
You may need to power off the printer, and power it back on. Then try and print.