Replace the entire waste ink pad assembly and reset the counter at an authorized service center. This costs around $50–$100, often more than the printer itself.
Never use an L120 or L3110 resetter on an L121. Using the wrong firmware tool can "brick" your printer (make it permanently unusable). Conclusion adjustment program for epson l121
Some newer Epson L121 firmware versions block unofficial adjustment programs. You may need to downgrade firmware first – a complex and risky process. Replace the entire waste ink pad assembly and