There are several steps to check when you encounter a low ink/toner warning on a recently replaced ink/toner cartridge:

1. Check that the correct cartridge model is installed in your printer.
2. Check the printer manufacturer's website for possible updates that may be required for your printer after installing the cartridge.
3. Check that the cartridge is locked to the printer by pushing the blue lever down.
4. If applicable, make sure that the chip is firmly seated in the cartridge slot.
5. Check printer settings to ensure that the cartridge is recognized.
6. Check to see if the printer is using a standard cartridge or a high yield cartridge.