DIAGNOSIS The internal maintenance box (ink absorber pads) is full. This is a hardware counter that triggers after a high number of cleaning cycles, common with heavy use or frequent power-cycling.
FIX For the ET-4850, this requires service. The maintenance box is not user-replaceable. You must contact Epson Support to arrange service.
1. Have your printer serial number ready (on the back or on a printed status sheet).
2. In the US, call 1-800-463-7766. They will run diagnostics remotely via the printer's panel if it's connected to the internet.
3. They will likely offer a mail-in repair for a flat fee or, if under warranty, a replacement.
IF THAT DIDN'T WORK If the printer is out of warranty and you want to avoid the fee, some independent repair shops can perform the reset and pad replacement, but it voids any remaining Epson support and requires disassembly.
HEADS UP The printer will eventually stop working entirely when the counter reaches zero. Continuing to use it with a full pad can cause ink to leak inside the machine, creating a bigger repair bill.