It is a non-critical part, the machine will print fine with that error displayed on the Fiery webtools and CWS.
The actual part is a filter and is not a customer replaceable unit. I am not sure how you would obtain one as it is a thing the techs typically replace while onsite.
Joe, that's not entirely accurate.
Generally the replace cleaning cartridge message will show on the Fiery bar or in Command Workstation. The 560 doesn't have a cleaning cartridge, this is a glitch that's reporting a 4110-family error on a similar machine.
More often than not the consumable causing the issue in this case will be the fuser, although it might be another one. Best thing to try is to look at the entire consumables list at the machine UI and see if any are in need of replacement soon.
Hope this helps, Mr. Reinhardtsen.