Diagnosis
This is the classic 'ink detection' hiccup. The printer's sensor isn't reading the ink level in the black tank correctly, usually because of a tiny air bubble or a slightly misaligned cartridge.
How to Fix It
First, power the printer off completely. Open the front access door and gently pull the black ink cartridge straight out. Give it a firm but careful shake (keep it upright) to dislodge any air. Re-seat it firmly until you hear/feel a solid click. Close the door and power back on. The printer should re-initialize and clear the error.
If That Didn't Work
Try cleaning the electrical contacts. Power off, unplug the printer. Remove the cartridge again and use a dry, lint-free cloth to gently wipe the copper-colored contacts on the cartridge and the slot inside the printer. Avoid touching them with your fingers. Reinstall, plug in, and power on.
Heads Up
Don't just keep re-seating it over and over while the printer is on—it can confuse the system further. Always cycle the power after making a physical change.